21525864 has 32 divisors (see below), whose sum is σ = 53965440. Its totient is φ = 7155200.

The previous prime is 21525857. The next prime is 21525883. The reversal of 21525864 is 46852512.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9304 + ... + 11384.

It is an arithmetic number, because the mean of its divisors is an integer number (1686420).

Almost surely, 2^21525864 is an apocalyptic number.

21525864 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21525864 is an abundant number, since it is smaller than the sum of its proper divisors (32439576).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21525864 is a wasteful number, since it uses less digits than its factorization.

21525864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2521 (or 2517 counting only the distinct ones).

The product of its digits is 19200, while the sum is 33.

The square root of 21525864 is about 4639.5973963265. The cubic root of 21525864 is about 278.1763455092.

The spelling of 21525864 in words is "twenty-one million, five hundred twenty-five thousand, eight hundred sixty-four".