21280804 has 36 divisors (see below), whose sum is σ = 40616100. Its totient is φ = 9748480.

The previous prime is 21280793. The next prime is 21280807. The reversal of 21280804 is 40808212.

It can be written as a sum of positive squares in 6 ways, for example, as 102400 + 21178404 = 320^2 + 4602^2 .

It is not an unprimeable number, because it can be changed into a prime (21280807) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 47172 + ... + 47620.

It is an arithmetic number, because the mean of its divisors is an integer number (1128225).

Almost surely, 2^21280804 is an apocalyptic number.

It is an amenable number.

21280804 is a deficient number, since it is larger than the sum of its proper divisors (19335296).

21280804 is a wasteful number, since it uses less digits than its factorization.

21280804 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 528 (or 509 counting only the distinct ones).

The product of its (nonzero) digits is 1024, while the sum is 25.

The square root of 21280804 is about 4613.1121815971. The cubic root of 21280804 is about 277.1166863626.

The spelling of 21280804 in words is "twenty-one million, two hundred eighty thousand, eight hundred four".