21056684 has 24 divisors (see below), whose sum is σ = 41948928. Its totient is φ = 9154640.

The previous prime is 21056681. The next prime is 21056689. The reversal of 21056684 is 48665012.

It is a self number, because there is not a number n which added to its sum of digits gives 21056684.

It is not an unprimeable number, because it can be changed into a prime (21056681) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9392 + ... + 11415.

It is an arithmetic number, because the mean of its divisors is an integer number (1747872).

Almost surely, 2^21056684 is an apocalyptic number.

It is an amenable number.

21056684 is a deficient number, since it is larger than the sum of its proper divisors (20892244).

21056684 is a wasteful number, since it uses less digits than its factorization.

21056684 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20845 (or 20843 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 32.

The square root of 21056684 is about 4588.7562585084. The cubic root of 21056684 is about 276.1404277336.

The spelling of 21056684 in words is "twenty-one million, fifty-six thousand, six hundred eighty-four".