21056648 has 16 divisors (see below), whose sum is σ = 39744960. Its totient is φ = 10458000.

The previous prime is 21056597. The next prime is 21056653. The reversal of 21056648 is 84665012.

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, 7508 + ... + 9923.

It is an arithmetic number, because the mean of its divisors is an integer number (2484060).

Almost surely, 2^21056648 is an apocalyptic number.

It is an amenable number.

21056648 is a deficient number, since it is larger than the sum of its proper divisors (18688312).

21056648 is a wasteful number, since it uses less digits than its factorization.

21056648 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17588 (or 17584 counting only the distinct ones).

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

The square root of 21056648 is about 4588.7523358752. The cubic root of 21056648 is about 276.1402703638.

The spelling of 21056648 in words is "twenty-one million, fifty-six thousand, six hundred forty-eight".