21331888 has 20 divisors (see below), whose sum is σ = 41438320. Its totient is φ = 10638144.

The previous prime is 21331873. The next prime is 21331897. The reversal of 21331888 is 88813312.

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, 5506 + ... + 8542.

It is an arithmetic number, because the mean of its divisors is an integer number (2071916).

Almost surely, 2^21331888 is an apocalyptic number.

It is an amenable number.

21331888 is a deficient number, since it is larger than the sum of its proper divisors (20106432).

21331888 is a wasteful number, since it uses less digits than its factorization.

21331888 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3484 (or 3478 counting only the distinct ones).

The product of its digits is 9216, while the sum is 34.

The square root of 21331888 is about 4618.6456889439. The cubic root of 21331888 is about 277.3382462353.

The spelling of 21331888 in words is "twenty-one million, three hundred thirty-one thousand, eight hundred eighty-eight".