I love numeric trivia, so here's one for you: The Lines Number.
Given a sum of single digit (decimal) numbers raised to single digit exponents. Take all the single digit numbers and the single digit exponents, and put them together in the order they appear to form a single, multi-digit number. There exists only one positive sum of this kind so that the answer to the sum equals the resulting multi-digit number:
40 - 33 + 79 - 56 = 40337956
The number was discovered by my geeky friend Glenn T. Lines in December 2005. Unfortunately, Glenn is too lazy to make a description of his own number. Hence, I do it for him. Unfortunately, I'm no good at describing math, so let's revisit the above paragraph, this time visually:
= 4 0 3 3 7 9 5 6
That the number is unique was demonstrated exhaustively, since there's an upper limit to how large such a number can be.