4007

This number is a prime.

The smallest "James Bond prime." Defined as any prime ending in 007. From PRIME NUMBERS: The Most Mysterious Figures in Math, by David Wells; John Wiley & Sons, Inc., 2005, p.228.

The only prime whose factorial ends with exactly one thousand 0's. [Beedassy]

The smallest five-digit Cyclops number (11011) is the sum of 4007 and its reverse (7004). [Gaydos]

The sum of the first 4007 distinct-digit numbers is the largest triangular number you can achieve in this manner. [Gaydos]