21302808 has 16 divisors (see below), whose sum is σ = 53257080. Its totient is φ = 7100928.

The previous prime is 21302789. The next prime is 21302833. The reversal of 21302808 is 80820312.

It is a Harshad number since it is a multiple of its sum of digits (24), and also a Moran number because the ratio is a prime number: 887617 = 21302808 / (2 + 1 + 3 + 0 + 2 + 8 + 0 + 8).

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, 443785 + ... + 443832.

Almost surely, 2^21302808 is an apocalyptic number.

It is an amenable number.

21302808 is an abundant number, since it is smaller than the sum of its proper divisors (31954272).

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

21302808 is a wasteful number, since it uses less digits than its factorization.

21302808 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 887626 (or 887622 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 24.

The square root of 21302808 is about 4615.4965063360. The cubic root of 21302808 is about 277.2121648220.

The spelling of 21302808 in words is "twenty-one million, three hundred two thousand, eight hundred eight".