21331975 has 24 divisors (see below), whose sum is σ = 30632960. Its totient is φ = 14433120.

The previous prime is 21331963. The next prime is 21331993. The reversal of 21331975 is 57913312.

It is not a de Polignac number, because 21331975 - 2⁷ = 21331847 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 13054 + ... + 14596.

Almost surely, 2^21331975 is an apocalyptic number.

21331975 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21331975 is a deficient number, since it is larger than the sum of its proper divisors (9300985).

21331975 is a wasteful number, since it uses less digits than its factorization.

21331975 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1639 (or 1634 counting only the distinct ones).

The product of its digits is 5670, while the sum is 31.

The square root of 21331975 is about 4618.6551072796. The cubic root of 21331975 is about 277.3386232670.

The spelling of 21331975 in words is "twenty-one million, three hundred thirty-one thousand, nine hundred seventy-five".