21937888 has 72 divisors (see below), whose sum is σ = 53261712. Its totient is φ = 8838144.

The previous prime is 21937879. The next prime is 21937897. The reversal of 21937888 is 88873912.

It is an interprime number because it is at equal distance from previous prime (21937879) and next prime (21937897).

Its product of digits (193536) is a multiple of the sum of its prime factors (864).

It is a congruent number.

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, 26245 + ... + 27067.

It is an arithmetic number, because the mean of its divisors is an integer number (739746).

Almost surely, 2^21937888 is an apocalyptic number.

21937888 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21937888, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26630856).

21937888 is an abundant number, since it is smaller than the sum of its proper divisors (31323824).

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

21937888 is a wasteful number, since it uses less digits than its factorization.

21937888 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 864 (or 849 counting only the distinct ones).

The product of its digits is 193536, while the sum is 46.

The square root of 21937888 is about 4683.7899184314. The cubic root of 21937888 is about 279.9399871383.

The spelling of 21937888 in words is "twenty-one million, nine hundred thirty-seven thousand, eight hundred eighty-eight".