21612736 has 28 divisors (see below), whose sum is σ = 44051728. Its totient is φ = 10513152.

The previous prime is 21612707. The next prime is 21612749. The reversal of 21612736 is 63721612.

It is a super-2 number, since 2×21612736² = 934220714811392, which contains 22 as substring.

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, 2196 + ... + 6931.

It is an arithmetic number, because the mean of its divisors is an integer number (1573276).

Almost surely, 2^21612736 is an apocalyptic number.

It is an amenable number.

21612736 is an abundant number, since it is smaller than the sum of its proper divisors (22438992).

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

21612736 is an equidigital number, since it uses as much as digits as its factorization.

21612736 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9176 (or 9166 counting only the distinct ones).

The product of its digits is 3024, while the sum is 28.

The square root of 21612736 is about 4648.9499889760. The cubic root of 21612736 is about 278.5500556283.

The spelling of 21612736 in words is "twenty-one million, six hundred twelve thousand, seven hundred thirty-six".