21057375 has 32 divisors (see below), whose sum is σ = 35335872. Its totient is φ = 11136000.

The previous prime is 21057341. The next prime is 21057419. The reversal of 21057375 is 57375012.

It is not a de Polignac number, because 21057375 - 2⁷ = 21057247 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 87255 + ... + 87495.

It is an arithmetic number, because the mean of its divisors is an integer number (1104246).

Almost surely, 2^21057375 is an apocalyptic number.

21057375 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21057375 is a deficient number, since it is larger than the sum of its proper divisors (14278497).

21057375 is a wasteful number, since it uses less digits than its factorization.

21057375 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 492 (or 482 counting only the distinct ones).

The product of its (nonzero) digits is 7350, while the sum is 30.

The square root of 21057375 is about 4588.8315506238. The cubic root of 21057375 is about 276.1434483256.

The spelling of 21057375 in words is "twenty-one million, fifty-seven thousand, three hundred seventy-five".