204

Number
$204$ (two hundred and four) is:


 * $2^2 \times 3 \times 17$


 * The $8$th square pyramidal number after $1, 5, 14, 30, 55, 91, 140$:
 * $140 = 1 + 4 + 9 + 16 + 25 + 36 + 49 + 64 = \displaystyle \sum_{k \mathop = 1}^8 k^2 = \dfrac {8 \left({8 + 1}\right) \left({2 \times 8 + 1}\right)} 6$


 * The $3$rd positive integer after $200, 202$ that cannot be made into a prime number by changing just $1$ digit

Also see

 * Sum of Cubes of 3 Consecutive Integers which is Square