21204464 has 20 divisors (see below), whose sum is σ = 41169240. Its totient is φ = 10580160.

The previous prime is 21204451. The next prime is 21204487. The reversal of 21204464 is 46440212.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8834 + ... + 10974.

It is an arithmetic number, because the mean of its divisors is an integer number (2058462).

Almost surely, 2^21204464 is an apocalyptic number.

It is an amenable number.

21204464 is a deficient number, since it is larger than the sum of its proper divisors (19964776).

21204464 is a wasteful number, since it uses less digits than its factorization.

21204464 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2768 (or 2762 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 23.

The square root of 21204464 is about 4604.8305071957. The cubic root of 21204464 is about 276.7849251705.

Adding to 21204464 its reverse (46440212), we get a palindrome (67644676).

The spelling of 21204464 in words is "twenty-one million, two hundred four thousand, four hundred sixty-four".