21086504 has 16 divisors (see below), whose sum is σ = 41618400. Its totient is φ = 9988272.

The previous prime is 21086501. The next prime is 21086543. The reversal of 21086504 is 40568012.

It is not an unprimeable number, because it can be changed into a prime (21086501) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 69212 + ... + 69515.

It is an arithmetic number, because the mean of its divisors is an integer number (2601150).

Almost surely, 2^21086504 is an apocalyptic number.

It is an amenable number.

21086504 is a deficient number, since it is larger than the sum of its proper divisors (20531896).

21086504 is a wasteful number, since it uses less digits than its factorization.

21086504 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 138752 (or 138748 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 26.

The square root of 21086504 is about 4592.0043553986. The cubic root of 21086504 is about 276.2707208579.

The spelling of 21086504 in words is "twenty-one million, eighty-six thousand, five hundred four".