It is a congruent number.
It is an unprimeable number.
21604688 is an apocalyptic number.
It is an amenable number.
It is a practical number, because each smaller number is the sum of distinct divisors of 1604688, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2099568).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
1604688 is a wasteful number, since it uses less digits than its factorization.
1604688 is an odious number, because the sum of its binary digits is odd.
The square root of 1604688 is about 1266.7628033693. The cubic root of 1604688 is about 117.0748297699.
The spelling of 1604688 in words is "one million, six hundred four thousand, six hundred eighty-eight".