21064375 has 10 divisors (see below), whose sum is σ = 26322824. Its totient is φ = 16851000.

The previous prime is 21064363. The next prime is 21064471. The reversal of 21064375 is 57346012.

It is not a de Polignac number, because 21064375 - 2⁷ = 21064247 is a prime.

It is a Duffinian number.

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 9 ways as a sum of consecutive naturals, for example, 16227 + ... + 17476.

Almost surely, 2^21064375 is an apocalyptic number.

21064375 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21064375 is a deficient number, since it is larger than the sum of its proper divisors (5258449).

21064375 is an frugal number, since it uses more digits than its factorization.

21064375 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33723 (or 33708 counting only the distinct ones).

The product of its (nonzero) digits is 5040, while the sum is 28.

The square root of 21064375 is about 4589.5942086420. The cubic root of 21064375 is about 276.1740439401.

The spelling of 21064375 in words is "twenty-one million, sixty-four thousand, three hundred seventy-five".