204

204 = 2 x 2 x 3 x 17.

204 is 11001100 in base 2 (binary).

204 is a nonagonal number and a square pyramidal number. It is also an abundant number.

The number 204ⁿ + 1 is prime for n = 2, 0, and 4.

204 is the square root of the triangular number 41616.

204² = 23³ + 24³ + 25³ = 41616.

204 is the sum of twin primes: 204 = 101 + 103.

204 is the number of different squares that you can find on a standard chessboard.

Source: Number Gossip