21031608 has 32 divisors (see below), whose sum is σ = 56624400. Its totient is φ = 6471168.

The previous prime is 21031559. The next prime is 21031627. The reversal of 21031608 is 80613012.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 33393 + ... + 34016.

Almost surely, 2^21031608 is an apocalyptic number.

It is an amenable number.

21031608 is an abundant number, since it is smaller than the sum of its proper divisors (35592792).

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

21031608 is a wasteful number, since it uses less digits than its factorization.

21031608 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 67431 (or 67427 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 21.

The square root of 21031608 is about 4586.0231137664. The cubic root of 21031608 is about 276.0307674165.

The spelling of 21031608 in words is "twenty-one million, thirty-one thousand, six hundred eight".