21965256 has 48 divisors (see below), whose sum is σ = 61698000. Its totient is φ = 7321104.

The previous prime is 21965249. The next prime is 21965351. The reversal of 21965256 is 65256912.

It is a super-2 number, since 2×21965256² = 964944942291072, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 21965256.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3706 + ... + 7593.

It is an arithmetic number, because the mean of its divisors is an integer number (1285375).

Almost surely, 2^21965256 is an apocalyptic number.

It is an amenable number.

21965256 is an abundant number, since it is smaller than the sum of its proper divisors (39732744).

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

21965256 is a wasteful number, since it uses less digits than its factorization.

21965256 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11320 (or 11304 counting only the distinct ones).

The product of its digits is 32400, while the sum is 36.

The square root of 21965256 is about 4686.7105735260. The cubic root of 21965256 is about 280.0563492033.

The spelling of 21965256 in words is "twenty-one million, nine hundred sixty-five thousand, two hundred fifty-six".