21655804 has 12 divisors (see below), whose sum is σ = 38922184. Its totient is φ = 10535184.

The previous prime is 21655787. The next prime is 21655813. The reversal of 21655804 is 40855612.

It is a hoax number, since the sum of its digits (31) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 73014 + ... + 73309.

Almost surely, 2^21655804 is an apocalyptic number.

It is an amenable number.

21655804 is a deficient number, since it is larger than the sum of its proper divisors (17266380).

21655804 is a wasteful number, since it uses less digits than its factorization.

21655804 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 146364 (or 146362 counting only the distinct ones).

The product of its (nonzero) digits is 9600, while the sum is 31.

The square root of 21655804 is about 4653.5796973943. The cubic root of 21655804 is about 278.7349563895.

The spelling of 21655804 in words is "twenty-one million, six hundred fifty-five thousand, eight hundred four".