21725568 has 48 divisors (see below), whose sum is σ = 62520900. Its totient is φ = 7241472.

The previous prime is 21725567. The next prime is 21725573. The reversal of 21725568 is 86552712.

It is a happy number.

21725568 is a `hidden beast` number, since 21 + 72 + 5 + 568 = 666.

It is a tau number, because it is divible by the number of its divisors (48).

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21725567) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 8278 + ... + 10581.

Almost surely, 2^21725568 is an apocalyptic number.

It is an amenable number.

21725568 is an abundant number, since it is smaller than the sum of its proper divisors (40795332).

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

21725568 is a wasteful number, since it uses less digits than its factorization.

21725568 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18879 (or 18864 counting only the distinct ones).

The product of its digits is 33600, while the sum is 36.

The square root of 21725568 is about 4661.0694051902. The cubic root of 21725568 is about 279.0339496977.

The spelling of 21725568 in words is "twenty-one million, seven hundred twenty-five thousand, five hundred sixty-eight".