9000

9000 = 2 x 2 x 2 x 3 x 3 x 5 x 5 x 5.

9000 has two representations as a sum of two squares: 9000 = 30² + 90² = 54² + 78².

9000 is the index of a triangular number containing only three different digits.

9000 is a centered cube number.

9000 is the number of palindromes of length 8 (A050683).

The BFG-9000 is the most powerful weapon in the video game series Doom.

Source: What's Special About This Number?