21265564 has 12 divisors (see below), whose sum is σ = 38080504. Its totient is φ = 10385424.

The previous prime is 21265553. The next prime is 21265577. The reversal of 21265564 is 46556212.

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 polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 61647 + ... + 61990.

Almost surely, 2^21265564 is an apocalyptic number.

It is an amenable number.

21265564 is a deficient number, since it is larger than the sum of its proper divisors (16814940).

21265564 is a wasteful number, since it uses less digits than its factorization.

21265564 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 123684 (or 123682 counting only the distinct ones).

The product of its digits is 14400, while the sum is 31.

The square root of 21265564 is about 4611.4600724716. The cubic root of 21265564 is about 277.0505192691.

The spelling of 21265564 in words is "twenty-one million, two hundred sixty-five thousand, five hundred sixty-four".