666 (number) on 1/149 in base 10 has a magic total of 666. The prime factorization of 666 is 2 • 3 • 37. Also, 666 is the sum of squares of first seven primes: formula_2 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). In the Textus Receptus manuscripts of the New Testament, the Book of Revelation () cryptically asserts 666 to be "man's number" or "the number of a
Japanese numerals , ). The Arabic numerals are more often used in horizontal writing, and the Chinese numerals are more common in vertical writing. Most numbers have two readings, one derived from Chinese used for cardinal numbers (On reading) and a native Japanese reading used somewhat less formally for numbers up to 10. In some cases (listed below) the Japanese reading is generally preferred for all uses. <nowiki>*</nowiki> The special reading 〇 "maru" (which means "round" or "circle") is also found. It may be optionally used when reading individual digits of a number one after another, instead of as a full number.