21880872 has 96 divisors (see below), whose sum is σ = 64744680. Its totient is φ = 6635520.

The previous prime is 21880849. The next prime is 21880879. The reversal of 21880872 is 27808812.

It can be written as a sum of positive squares in 4 ways, for example, as 17189316 + 4691556 = 4146^2 + 2166^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (21880879) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 90672 + ... + 90912.

Almost surely, 2^21880872 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21880872, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32372340).

21880872 is an abundant number, since it is smaller than the sum of its proper divisors (42863808).

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

21880872 is a wasteful number, since it uses less digits than its factorization.

21880872 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 363 (or 356 counting only the distinct ones).

The product of its (nonzero) digits is 14336, while the sum is 36.

The square root of 21880872 is about 4677.6994345511. The cubic root of 21880872 is about 279.6972578205.

The spelling of 21880872 in words is "twenty-one million, eight hundred eighty thousand, eight hundred seventy-two".