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
Roman numerals large numbers. Similarly, | for 5,000 was reduced to ↁ; | for 10,000 to ↂ; | for 50,000 to ↇ; and | for 100,000 to ↈ. Another system is the "vinculum", in which conventional Roman numerals are multiplied by 1,000 by adding an "bar" or "overline". Although mathematical historian David Eugene Smith disputes that this was part of ancient Roman usage, the notation was certainly in use in the Middle Ages, and is sometimes suggested as a workable method for modern use, although it is not standardised as such. Any hundreds, tens or units in the number are written in