21625808 has 20 divisors (see below), whose sum is σ = 42171780. Its totient is φ = 10742784.

The previous prime is 21625787. The next prime is 21625811. The reversal of 21625808 is 80852612.

It can be written as a sum of positive squares in 2 ways, for example, as 5721664 + 15904144 = 2392^2 + 3988^2 .

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, 1793 + ... + 6816.

It is an arithmetic number, because the mean of its divisors is an integer number (2108589).

Almost surely, 2^21625808 is an apocalyptic number.

It is an amenable number.

21625808 is a deficient number, since it is larger than the sum of its proper divisors (20545972).

21625808 is a wasteful number, since it uses less digits than its factorization.

21625808 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8774 (or 8768 counting only the distinct ones).

The product of its (nonzero) digits is 7680, while the sum is 32.

The square root of 21625808 is about 4650.3556853213. The cubic root of 21625808 is about 278.6062026531.

The spelling of 21625808 in words is "twenty-one million, six hundred twenty-five thousand, eight hundred eight".