In numbers, 666 (LH:24), i.e. six-hundred and sixty-six, is the sum of the numbers inside (6 + 32 + 3 ... 2 + 31 = 666) of the solar magic square, shown adjacent; the sum of the sums (111 + 111 + ... + 111 = 666) of the six rows (or six columns) of the solar magic square; a sacred number (Pythagoras, 550BC); the isopsephy value of the god Serapis (aka "Osiris-Apis"), or "ο Σεραπις" (NE:666) in Greek, an early form of Christ worshiped in Egypt (Hadrian, 126AD); in music theory, the string ratio of the perfect fifth (0.666); a cypher of the word "gold", via Latin word “Aurelium”, a substance thought to be related to the sun; the number of the beast, in later versions of Christianity.
Pythagoras | 666 and 888
The following is another take on this:
- “These elements include a combination of hanging and crucifixion, death and resurrection, and important celestial, solar, and numerical elements, such as the inclusion of twelve disciples, thus highlighting the number 12 and 13: twelve spheres around a central sphere. ‘The ancients discovered that if a sphere is surrounded by others of exactly the same dimension so that all of the spheres are in contact with each other, the central sphere will be surrounded by exactly 12 others' (Freke & Gandy, 1999, p. 42). Most savior-gods around whom religions formed had twelve disciples (Mangasarian, 2004). Other sacred numbers also appear in many traditions, including die numbers 7, 3, 40, 666, and 888; the last two are sacred numbers in the Pythagorean faith (which relate to the Chinese concepts of yin and yang, the Japanese concepts of in and yo, and the Hindu ideas of Shiva and Pavarti, who are represented iconographical as the same being). Pythagoras, son of the god Apollo, was supposedly born of a virgin. His birth was miraculous. He studied religion from the Egyptian priests and later became a prophet in Greece and Italy, which provides further circumstantial evidence of the profound influence the Egyptian religion has had on Western faiths.”
- — Ken Jeremiah (2014), Eternal Remains (pg. 102)
The number 666 translates into the ratio 6:9, which expresses the perfect 5th, and the number 888 translates into the ratio 9:8, which expresses a whole tone:
- “In Pythagorean musical proportion, the perfect 5th is expressed as the ratio of 6:9. From this he deduced by simple math, the number 0.666 (6 divided by 9). The number 666 we will discuss later. Pythagorean musical proportion also produces the ratio of 9:8, which expresses a whole tone. By a similar simple calculation, we can deduce the mystical number of 888. This number had great significance for the ancient Greeks for it was the gematria of the sacred first priest of Apollo, called Olen. It's worth mentioning here that the founders of early Christianity were well versed in the science and they knew the significance of this number 888, when they created their godman, their first sacred high priest, Jesus. The name Jesus is a transliteration from the original Aramaic and when it was introduced into the Greek texts, the spelling was adjusted so that the gematria of the name would be 888. Jesus is the 888 of the Gospels. He was created along with his name to be the Ogdoad of eights, the powerful triplicity of 8, the number of regeneration and indeed, the number of resurrection.”
- — Geoff Roberts (2011), Jesus 888 (pg. 235)
The following, to given an alternative rendition, attempts to render 666 as disharmony:
- “Pythagoras is also known for numerology. He believes that everything in the universe can be represented numerically, and that words can express numbers and mathematical relationships. This was called gematria, and the most known numerical representations that Pythagoras initiated are the musical ratios for harmony (.888) and disharmony (.666). Hundreds of years later, the Gnostic schizophrenic St. John would use 888 to represent Yoshua and 666 to represent the "Beast" (Revelations 13:18).”
- — Rodney Michael (2002), Illuminati: Healing and Developing the Mind (pg. 121)
These two numbers, whatever the case, presumably, to Pythagoras, had connection to solar magic square?
Solar magic square
The solar square is unique in that the number "666" reoccurs frequently in religio-mythology; for example:
- “The fourth tablet is of the sun, and is made of a square of 6, and contains 36 numbers, whereof 6 on every side and diameter, produce 111, and the sum of all is 666. This being engraven on a golden plate, renders him who wears it renowned and amiable, and equals a man to kings and princes . . . but with an unfortunate sun it makes a tyrant. The numbers of this square are all curiously appropriate to the sun, whose ark has been shown to measure 666 of its diameters. Again, 666 is the diameter of a circle 2,093 in circumference, and 2,093 is 92 times the diameter of the sun's orbit as well as the diameter of the circle containing the square whose sides are 1,480, — the measure of the body of Christos.”
- “The square of the sun has six rows of six figures, using the numbers 1 to 36, and if all the figures in the square are added the total is 666. The deduction which magicians draw from this is that the Beast of Revelation is one aspect of the sun or life force. It is the savage, relentless pulsing power which derives all living things to procreate, to survive, to master their environment.”
- — Richard Cavendish (1967), The Black Arts (pgs. 130-31)
Osiris-Apis | Serapis
In 126AD, Hadrian, Roman emperor, during his tour of Egypt, reported that Serapis worshipers were Christians. The Greek name of Serapis: ο Σεραπις, aka "Osiris-Apis", a synretism of the gods Osiris and Apis, has an isopsephy value of 666. In the Roman recension, the joint god Osiris-Horus became rescripted into the character of Jesus Christ. In the Bible, the character Lazarus, meaning: "The Osiris", equates to: "ο Σεραπις" (NE:666), meaning: "The Serapis".
The the number "666", in this sense, could have been interpreted in this period in the sense of the joint god "Osiris-Horus", coded in the number pair "666-888", Osiris being "666" and Horus (knowing that Jesus = 888) being "888", who was reduced mono-theistically into the man Jesus. The of this is corroborated by the known fact that in the late New Kingdom era (1250-1050 BCM), Osiris was joined to the “sun” (Ra) via the joint god Osiris-Ra. Alternatively, Osiris (666) as the father, and Horus (888) as the son, possibly?
Perfect fifth | 0.666
The number 0.666 or 2/3, in Pythagorean tuning, represents the descending "perfect fifth" (frequency ratio of 3:2 ascending or 2:3 descending), which is a frequency ratio of pitches that is pleasing to the ear. One take on this is as follows:
- “Helios, 318, the Greek name of the sun, is derived from the ratio of the circle, for the reciprocal of π is .318. In other words, a circle measuring 1000 units in circumference (representing unity) will have a diameter of 318 units. In music, .666 is the string ratio of the perfect fifth, while .888 is the string ratio of the whole tone. The Greeks did not use the decimal point at all, and, in every instance where gematria values are based on mathematical ratios, the ‘decimal point’ has been moved over exactly three places. In other words, while we define these ratios in relation to ‘1’, we conclude that the Greeks defined these ratios in relation to ‘1000’, which represents the same principle, the monad or unity, the ineffable first cause.”
- — David Fideler (1993), Jesus Christ, Sun of God: Ancient Cosmology and Early Christian Symbolism (pg. 84) 
Aurelium | Gold | Sun
- “SATOR square as a good number, it is impossible to associate its origin with a pejorative use of an imperial name. The 666 in the TENET cross, then, may stand for AYPEXION EHMA, solar symbol or sun sign (Lilliebjorn, c.1933).”
- — Walter Moeller (1973), The Mithraic Origin and Meanings of the Rotas-Sator Square (pg. 19) 
In 1973, Richard Moeller attempts to connect the 666 solar symbolism to Tenet and the Sator square, via Mithras mythology (the Persian rescript of the Osiris-Horus + Ra mythos), as shown adjacent.
Number of the beast
In Christian mythology, the number "666" came to be called the number of the beast.
The following are quotes:
- “It will be noticed that the great number of Sol is 666, called Sorath, SURT, the number of the Beast, about which so much folly has been written. One famous square of five times five divisions, amounting in most directions to 666 is formed of the mystic words sator, arepo, tenet, opera, rotas. Of these, the first, third, and last number 666, but opera and its reverse number only 356. The number 608 is notable, being in Coptic, PHRE, the Sun 500, 100, 8 and in Greek we find VHS, 400, 8, 200, which becomes IHS in Latin, for the Greek Upsilon changes to Y and I in Latin, and so we obtain the anagram of ‘Iesus hominum Salvator’.”
- — William Westcott (1889), Numbers: Their Occult Powers and Mystic Virtues (pg. 16) 
- “666 is the pet number of Godfrey Higgins, as referred to Rasit (RSVT), 200+60+6+400, which he insists means ‘wisdom’ — or as most believe — beginning or principle. 801 is the number of alpha and omega, 1+800, the Peristera or dove, vehicle of the ‘holy ghost’; being 80+5++100+200+300+5+100+1 = 801.”
- — William Westcott (1890), Numbers: Their Occult Powers and Mystic Virtues (pg. 50) 
- “The letters are arranged so as to read: ‘Sator Arepo Tenet Opera Rotas’, which has the look of a Latin epigram, but it is apparently untranslatable. We know that the priests sometimes converted Roman letters into Greek, so as to obtain numbers from them, as for instance in Kircher’s Oedipus Aegyptiacus  (§2.1, pg. 219), where various Latin words are written in Greek letters which bring out the number 666. If we give the letters of this seal the value of their Greek equivalents, we get 25 numbers, which may be read in various ways. The five letters on the four sides of the square form the word Sator, the ‘Sower’, or backwards ‘Rotas’, wheels. This word, written in Greek letters, has the numerical value of 671, the number of Thora, the Hebrew Bride, and óxóopos = 670. Then the sum of the numbers forming the perimeter of the square is 2084, or the length of the side of the Holy Oblation. The two middle rows of letters make up the word ‘Tenet’, read vertically and horizontally, and the numerical value of this word written in Greek letters is 660, or the number of miles in the diameter of the earth divided by 12. The four letters, which occur at the angles of the cross formed by the word ‘Tenet’, are equal to 360”
- — William Sterling (1897), The Cannon (pgs. 271-72)
- Sinclaire, Aloixa. (2016). “The Sun’s Magic Square” (666, 4:15-), YT, Jun 17.
- Jeremiah, Ken. (2014). Eternal Remains: World Mummification and the Beliefs that make it Necessary (pg. 102). Publisher.
- Roberts, Geoff. (2011). Jesus (pg. 235). Troubador.
- Michael, Rodney. (2002). Illuminati: Healing and Developing the Mind (pg. 121). Publisher.
- Nguiagain, Titus. (2001). “666 Origins”, Cosmos2000.Chez.com.
- Stirling, William. (1897). The Canon: an Exposition of Pagan Mystery Perpetuated in the Cabala as the Rule of All the Arts (pg. 271). Matthews.
- Silent historians problem – Hmolpedia 2020.
- Ο Σέραπις (Serapis) – Greek Wikipedia.
- Barry, Kieren. (1999). The Greek Qabalah: Alphabetic Mysticism and Numerology in the Ancient World (pdf) (Appendix II: Dictionary of Isopsephy, pgs. 215-271). Weiser.
- (a) Lazarus – Hmolpedia 2020.
(b) Raising of Lazarus – Hmolpedia 2020.
- Osiris-Horus – Hmolpedia 2020.
- Osiris-Ra – Hmolpedia.
- Perfect fifth – Wikipedia.
- Fideler, David. (1993). Jesus Christ, Sun of God: Ancient Cosmology and Early Christian Symbolism (318, 6+ pgs). Quest Books.
- Moeller, Walter. (1973). The Mithraic Origin and Meaning of the Rotas-Sator Square (pgs. 12-19). Brill, 70-pgs.
- Number of the beast – Wikipedia.
- (a) William, Westcott. (1989). “Numbers: Their Occult Powers and Mystic Virtues” (pg. 121), Lucifer, 5(25):117-124.
(b) William Wynn Wescott – Wikipedia.
- Anon. (1891). The Computation of 666: and Its Relation to Antichristian Systems, But Having Reference to a Person: The Coming Antichrist, who is to be Overthrown by the Sun of Righteousness. Nisbet.
- 666 – Wikipedia.