Since 36 is also triangular, 666 is a doubly triangular number.[5] Also, 36 = 15 + 21 where 15 and 21 are triangular as well, whose squares (152 = 225 and 212 = 441) add to 666 and have a difference of 216 = 6 × 6 × 6.
666 is also the sum of the squares of the first seven primes(22 + 32 + 52 + 72 + 112 + 132 + 172),[7][10] while the number of twin primes less than 66 + 666 is 666.[11]
The Roman numeral for 666, DCLXVI, has exactly one occurrence of all symbols whose value is less than 1000 in decreasing order (D = 500, C = 100, L = 50, X = 10, V = 5, I = 1).[7]
In the Textus Receptus manuscripts of the New Testament, the Book of Revelation (13:17–18) cryptically asserts 666 to be "the man's number" or "the number of a man" (depending on how the text is translated) associated with the Beast, an antagonistic creature that appears briefly about two-thirds into the apocalyptic vision. Some manuscripts[which?] of the original Koine Greek use the symbols χξϛ chixistigma (or χξϝ with a digamma), while other manuscripts spell out the number in words.[16]
In modern popular culture, 666 has become one of the most widely recognized symbols for the Antichrist or, alternatively, the devil. Earnest references to the number occur both among apocalypticist Christian groups and in explicitly anti-Christian subcultures.
References in contemporary Western art or literature are, more likely than not, intentional references to the Beast symbolism. Such popular references are therefore too numerous to list.
It is common to see the symbolic role of the integer 666 transferred to the numerical digit sequence 6-6-6. Some people take the Satanic associations of 666 so seriously that they actively avoid things related to 666 or the digits 6-6-6. This is known as hexakosioihexekontahexaphobia.
The Number of the Beast is cited as 616 in some early biblical manuscripts, the earliest known instance being in Papyrus 115.[17][18]
Using gematria, Neron Caesar transliterated from Greek into Hebrew short-form spelling, נרון קסר, produces the number 666. The Latin spelling of "Nero Caesar" transliterated into Ktiv haser Hebrew, נרו קסר, produces the number 616. Thus, in the Bible, 666 may have been a coded reference to Nero, who was the Roman emperor from 55 to 68 AD.[19] Though historic protestants such as Andreas Helwig in 1612 proposed the application of the Isopsephy principle to the papal name Vicarius Filii Dei.[20]
Is the magic sum, or sum of the magic constants of a six by six magic square, any row or column of which adds up to 111.
Is the sum of all the numbers on a roulette wheel (0 through 36).[19] This is a corollary of the fact that the number is a Triangular number, as mentioned earlier.
Was a winning lottery number in the 1980 Pennsylvania Lottery scandal, in which equipment was tampered to favor a 4or6 as each of the three individual random digits.[21]
Was the original name of the Macintosh SevenDust computer virus that was discovered in 1998.[citation needed] It is also the name of an extension that SevenDust can add to an uninfected Macintosh.[22]
InChinese numerology, the number is considered to be lucky and is often displayed in shop windows and neon signs.[25][26] In China, 666 can mean "everything goes smoothly" (the number six has the same pronunciation as the character 溜, which means "smooth".[27]
Where, sin(666°) = cos(216)° = −φ/2, also equivalently −cos(36°).
^149 and 151 also generate a twin-prime sum equal to 300, which is the 24th triangular number.
^It is the number 11110...109877666779011...011111 (241 digits long), with an equal amount of digits (119) that precede and follow a central 666 string (that also contains all sixes in the number). It is the twenty-seventh indexed member within the sequence of unique primes (where 33 = 27).
^Beale, Gregory K. (1999). The Book of Revelation: A Commentary on the Greek Text. Grand Rapids, Michigan: Wm. B. Eerdmans Publishing. p. 718. ISBN080282174X. Retrieved 9 July 2012.
^"Revelation 13:18". Stephanus New Testament. Bible Gateway. Retrieved 2006-06-22.
^Novum Testamentum Graece, Nestle and Aland, 1991, footnote to verse 13:18 of Revelation, page 659: "-σιοι δέκα ἕξ" as found in C [C=Codex Ephraemi Rescriptus]; for English see Metzger's Textual Commentary on the Greek New Testament, note on verse 13:18 of Revelation, page 750: "the numeral 616 was also read ..."