21873972 has 48 divisors (see below), whose sum is σ = 53215232. Its totient is φ = 6985440.

The previous prime is 21873967. The next prime is 21873977. The reversal of 21873972 is 27937812.

It is an interprime number because it is at equal distance from previous prime (21873967) and next prime (21873977).

It is a self number, because there is not a number n which added to its sum of digits gives 21873972.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21873977) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 47013 + ... + 47475.

Almost surely, 2^21873972 is an apocalyptic number.

It is an amenable number.

21873972 is an abundant number, since it is smaller than the sum of its proper divisors (31341260).

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

21873972 is a wasteful number, since it uses less digits than its factorization.

21873972 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 628 (or 626 counting only the distinct ones).

The product of its digits is 42336, while the sum is 39.

The square root of 21873972 is about 4676.9618343536. The cubic root of 21873972 is about 279.6678544527.

The spelling of 21873972 in words is "twenty-one million, eight hundred seventy-three thousand, nine hundred seventy-two".