21646536 has 32 divisors (see below), whose sum is σ = 54267360. Its totient is φ = 7195392.

The previous prime is 21646523. The next prime is 21646543. The reversal of 21646536 is 63564612.

It is a junction number, because it is equal to n+sod(n) for n = 21646497 and 21646506.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9351 + ... + 11433.

It is an arithmetic number, because the mean of its divisors is an integer number (1695855).

Almost surely, 2^21646536 is an apocalyptic number.

It is an amenable number.

21646536 is an abundant number, since it is smaller than the sum of its proper divisors (32620824).

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

21646536 is a wasteful number, since it uses less digits than its factorization.

21646536 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2525 (or 2521 counting only the distinct ones).

The product of its digits is 25920, while the sum is 33.

The square root of 21646536 is about 4652.5837982781. The cubic root of 21646536 is about 278.6951874637.

The spelling of 21646536 in words is "twenty-one million, six hundred forty-six thousand, five hundred thirty-six".