21937668 has 48 divisors (see below), whose sum is σ = 52711680. Its totient is φ = 7098624.

The previous prime is 21937639. The next prime is 21937679. The reversal of 21937668 is 86673912.

It is a happy number.

It is a super-2 number, since 2×21937668² = 962522554556448, which contains 22 as substring.

It is a hoax number, since the sum of its digits (42) 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 15 ways as a sum of consecutive naturals, for example, 69046 + ... + 69362.

It is an arithmetic number, because the mean of its divisors is an integer number (1098160).

Almost surely, 2^21937668 is an apocalyptic number.

It is an amenable number.

21937668 is an abundant number, since it is smaller than the sum of its proper divisors (30774012).

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

21937668 is a wasteful number, since it uses less digits than its factorization.

21937668 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 476 (or 474 counting only the distinct ones).

The product of its digits is 108864, while the sum is 42.

The square root of 21937668 is about 4683.7664331177. The cubic root of 21937668 is about 279.9390513599.

The spelling of 21937668 in words is "twenty-one million, nine hundred thirty-seven thousand, six hundred sixty-eight".