21708872 has 32 divisors (see below), whose sum is σ = 42854400. Its totient is φ = 10289664.

The previous prime is 21708859. The next prime is 21708893. The reversal of 21708872 is 27880712.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 22904 + ... + 23832.

It is an arithmetic number, because the mean of its divisors is an integer number (1339200).

Almost surely, 2^21708872 is an apocalyptic number.

It is an amenable number.

21708872 is a deficient number, since it is larger than the sum of its proper divisors (21145528).

21708872 is a wasteful number, since it uses less digits than its factorization.

21708872 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1085 (or 1081 counting only the distinct ones).

The product of its (nonzero) digits is 12544, while the sum is 35.

The square root of 21708872 is about 4659.2780556648. The cubic root of 21708872 is about 278.9624526066.

The spelling of 21708872 in words is "twenty-one million, seven hundred eight thousand, eight hundred seventy-two".