21386804 has 12 divisors (see below), whose sum is σ = 38717700. Its totient is φ = 10324608.

The previous prime is 21386797. The next prime is 21386819. The reversal of 21386804 is 40868312.

It can be written as a sum of positive squares in 2 ways, for example, as 3763600 + 17623204 = 1940^2 + 4198^2 .

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 3 ways as a sum of consecutive naturals, for example, 92069 + ... + 92300.

It is an arithmetic number, because the mean of its divisors is an integer number (3226475).

Almost surely, 2^21386804 is an apocalyptic number.

It is an amenable number.

21386804 is a deficient number, since it is larger than the sum of its proper divisors (17330896).

21386804 is a wasteful number, since it uses less digits than its factorization.

21386804 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 184402 (or 184400 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 32.

The square root of 21386804 is about 4624.5869004701. The cubic root of 21386804 is about 277.5760319757.

The spelling of 21386804 in words is "twenty-one million, three hundred eighty-six thousand, eight hundred four".