21528904 has 32 divisors (see below), whose sum is σ = 42379200. Its totient is φ = 10239040.

The previous prime is 21528893. The next prime is 21528929. The reversal of 21528904 is 40982512.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15819 + ... + 17125.

It is an arithmetic number, because the mean of its divisors is an integer number (1324350).

Almost surely, 2^21528904 is an apocalyptic number.

It is an amenable number.

21528904 is a deficient number, since it is larger than the sum of its proper divisors (20850296).

21528904 is a wasteful number, since it uses less digits than its factorization.

21528904 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1413 (or 1409 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 31.

The square root of 21528904 is about 4639.9249993938. The cubic root of 21528904 is about 278.1894400867.

The spelling of 21528904 in words is "twenty-one million, five hundred twenty-eight thousand, nine hundred four".