21330656 has 24 divisors (see below), whose sum is σ = 42625800. Its totient is φ = 10505088.

The previous prime is 21330649. The next prime is 21330679. The reversal of 21330656 is 65603312.

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, 2831 + ... + 7118.

It is an arithmetic number, because the mean of its divisors is an integer number (1776075).

Almost surely, 2^21330656 is an apocalyptic number.

It is an amenable number.

21330656 is a deficient number, since it is larger than the sum of its proper divisors (21295144).

21330656 is an equidigital number, since it uses as much as digits as its factorization.

21330656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10026 (or 10018 counting only the distinct ones).

The product of its (nonzero) digits is 3240, while the sum is 26.

The square root of 21330656 is about 4618.5123145879. The cubic root of 21330656 is about 277.3329070095.

Adding to 21330656 its reverse (65603312), we get a palindrome (86933968).

The spelling of 21330656 in words is "twenty-one million, three hundred thirty thousand, six hundred fifty-six".