21859872 has 24 divisors (see below), whose sum is σ = 57382416. Its totient is φ = 7286592.

The previous prime is 21859843. The next prime is 21859897. The reversal of 21859872 is 27895812.

It is a tau number, because it is divible by the number of its divisors (24).

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, 113758 + ... + 113949.

It is an arithmetic number, because the mean of its divisors is an integer number (2390934).

Almost surely, 2^21859872 is an apocalyptic number.

It is an amenable number.

21859872 is an abundant number, since it is smaller than the sum of its proper divisors (35522544).

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

21859872 is a wasteful number, since it uses less digits than its factorization.

21859872 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 227720 (or 227712 counting only the distinct ones).

The product of its digits is 80640, while the sum is 42.

The square root of 21859872 is about 4675.4542025348. The cubic root of 21859872 is about 279.6077500763.

The spelling of 21859872 in words is "twenty-one million, eight hundred fifty-nine thousand, eight hundred seventy-two".