" Just to point out that the no. 666 is actually DCLXVI in roman numerals, and that D,C,L,X,V and I, in turn, are the first six symbols in the roman numerical system in reverse order (i.e. I, V, X, L, C and D backwards). It's like us writing 9,8,7,6,5,4,3,2,1,0, and then someone coming along to add them all up to get 45! "

http://www.sciforums.com/threads/666-dclxvi-merely-first-6-roman-numerals-in-order.35951/