21256912 has 20 divisors (see below), whose sum is σ = 41292000. Its totient is φ = 10600928.

The previous prime is 21256909. The next prime is 21256931. The reversal of 21256912 is 21965212.

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, 5589 + ... + 8587.

It is an arithmetic number, because the mean of its divisors is an integer number (2064600).

Almost surely, 2^21256912 is an apocalyptic number.

It is an amenable number.

21256912 is a deficient number, since it is larger than the sum of its proper divisors (20035088).

21256912 is a wasteful number, since it uses less digits than its factorization.

21256912 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3450 (or 3444 counting only the distinct ones).

The product of its digits is 2160, while the sum is 28.

The square root of 21256912 is about 4610.5218793538. The cubic root of 21256912 is about 277.0129410472.

The spelling of 21256912 in words is "twenty-one million, two hundred fifty-six thousand, nine hundred twelve".