21804264 has 24 divisors (see below), whose sum is σ = 59053410. Its totient is φ = 7268064.

The previous prime is 21804247. The next prime is 21804269. The reversal of 21804264 is 46240812.

It can be written as a sum of positive squares in only one way, i.e., 21068100 + 736164 = 4590^2 + 858^2 .

It is a tau number, because it is divible by the number of its divisors (24).

It is not an unprimeable number, because it can be changed into a prime (21804269) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 151347 + ... + 151490.

Almost surely, 2^21804264 is an apocalyptic number.

21804264 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21804264 is an abundant number, since it is smaller than the sum of its proper divisors (37249146).

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

21804264 is a wasteful number, since it uses less digits than its factorization.

21804264 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 302849 (or 302842 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 27.

The square root of 21804264 is about 4669.5036138759. The cubic root of 21804264 is about 279.3704563620.

The spelling of 21804264 in words is "twenty-one million, eight hundred four thousand, two hundred sixty-four".