21328975 has 6 divisors (see below), whose sum is σ = 26447960. Its totient is φ = 17063160.

The previous prime is 21328969. The next prime is 21328987. The reversal of 21328975 is 57982312.

It is not a de Polignac number, because 21328975 - 2⁵ = 21328943 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 426555 + ... + 426604.

Almost surely, 2^21328975 is an apocalyptic number.

21328975 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21328975 is a deficient number, since it is larger than the sum of its proper divisors (5118985).

21328975 is an equidigital number, since it uses as much as digits as its factorization.

21328975 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 853169 (or 853164 counting only the distinct ones).

The product of its digits is 30240, while the sum is 37.

The square root of 21328975 is about 4618.3303259944. The cubic root of 21328975 is about 277.3256215817.

The spelling of 21328975 in words is "twenty-one million, three hundred twenty-eight thousand, nine hundred seventy-five".