21856944 has 20 divisors (see below), whose sum is σ = 56463896. Its totient is φ = 7285632.

The previous prime is 21856937. The next prime is 21856979. The reversal of 21856944 is 44965812.

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, 227629 + ... + 227724.

Almost surely, 2^21856944 is an apocalyptic number.

21856944 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21856944 is an abundant number, since it is smaller than the sum of its proper divisors (34606952).

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

21856944 is a wasteful number, since it uses less digits than its factorization.

21856944 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 455364 (or 455358 counting only the distinct ones).

The product of its digits is 69120, while the sum is 39.

The square root of 21856944 is about 4675.1410673904. The cubic root of 21856944 is about 279.5952655865.

The spelling of 21856944 in words is "twenty-one million, eight hundred fifty-six thousand, nine hundred forty-four".