21056575 has 12 divisors (see below), whose sum is σ = 26748288. Its totient is φ = 16433600.

The previous prime is 21056573. The next prime is 21056593. The reversal of 21056575 is 57565012.

It is not a de Polignac number, because 21056575 - 2¹ = 21056573 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21056573) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 9247 + ... + 11296.

It is an arithmetic number, because the mean of its divisors is an integer number (2229024).

Almost surely, 2^21056575 is an apocalyptic number.

21056575 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21056575 is a deficient number, since it is larger than the sum of its proper divisors (5691713).

21056575 is a wasteful number, since it uses less digits than its factorization.

21056575 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20594 (or 20589 counting only the distinct ones).

The product of its (nonzero) digits is 10500, while the sum is 31.

The square root of 21056575 is about 4588.7443816364. The cubic root of 21056575 is about 276.1399512522.

The spelling of 21056575 in words is "twenty-one million, fifty-six thousand, five hundred seventy-five".