21003304 has 16 divisors (see below), whose sum is σ = 45007200. Its totient is φ = 9001392.

The previous prime is 21003299. The next prime is 21003329. The reversal of 21003304 is 40330012.

It is a super-2 number, since 2×21003304² = 882277557832832, which contains 22 as substring.

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, 187474 + ... + 187585.

It is an arithmetic number, because the mean of its divisors is an integer number (2812950).

Almost surely, 2^21003304 is an apocalyptic number.

It is an amenable number.

21003304 is an abundant number, since it is smaller than the sum of its proper divisors (24003896).

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

21003304 is a wasteful number, since it uses less digits than its factorization.

21003304 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 375072 (or 375068 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 13.

The square root of 21003304 is about 4582.9361767321. The cubic root of 21003304 is about 275.9068859039.

Adding to 21003304 its reverse (40330012), we get a palindrome (61333316).

The spelling of 21003304 in words is "twenty-one million, three thousand, three hundred four".