2400 = 2 x 2 x 2 x 2 x 2 x 3 x 5 x 5.
2400 is 6666 in base 7.
2400 is a number that can be expressed as the difference of the squares of primes in just two distinct ways (A090788).
2400 is the total number triangles visible in a regular decagon with all diagonals drawn (A006600).
2400 is the number of ways of writing 11 as a sum of six squares (A000141).
2400 is the difference of two fourth powers (A147857).
Source: What's Special About This Number?