21604608 has 54 divisors (see below), whose sum is σ = 62298054. Its totient is φ = 7200768.

The previous prime is 21604601. The next prime is 21604621. The reversal of 21604608 is 80640612.

It can be written as a sum of positive squares in only one way, i.e., 14379264 + 7225344 = 3792^2 + 2688^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21604601) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2385 + ... + 6992.

Almost surely, 2^21604608 is an apocalyptic number.

It is an amenable number.

21604608 is an abundant number, since it is smaller than the sum of its proper divisors (40693446).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21604608 is an equidigital number, since it uses as much as digits as its factorization.

21604608 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9399 (or 9382 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 27.

The square root of 21604608 is about 4648.0757308805. The cubic root of 21604608 is about 278.5151327210.

The spelling of 21604608 in words is "twenty-one million, six hundred four thousand, six hundred eight".