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
Arabic numerals a royal document of 1456. By the mid-16th century, they were in common use in most of Europe. Roman numerals remained in use mostly for the notation of anno Domini years, and for numbers on clockfaces. Today, Roman numerals are still used for enumeration of lists (as an alternative to alphabetical enumeration), for sequential volumes, to differentiate monarchs or family members with the same first names, and (in lower case) to number pages in prefatory material in books. Cyrillic numerals were a numbering system derived from the Cyrillic alphabet, used by South and East Slavic peoples. The system was used