8400

8400 = 2 x 2 x 2 x 2 x 3 x 5 x 5 x 7.

8400 is a number with four distinct prime factors {2, 3, 5, 7} (A147571).

8400 is a pentagonal number (A000326).

8400 is the number of ways of writing 31 as the sum of seven triangular numbers (A226252).

8400 is 1100 in base 20.

8400 is a number that can be expressed as the difference of the squares of primes in just three distinct ways (A090782).

8400 divides 43⁴ - 1.

8400 is the number of legal queen moves in chess.

Source: Number Gossip