21900872 has 64 divisors (see below), whose sum is σ = 49144320. Its totient is φ = 8955648.

The previous prime is 21900833. The next prime is 21900883. The reversal of 21900872 is 27800912.

It is a happy number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 139418 + ... + 139574.

It is an arithmetic number, because the mean of its divisors is an integer number (767880).

Almost surely, 2^21900872 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 21900872, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24572160).

21900872 is an abundant number, since it is smaller than the sum of its proper divisors (27243448).

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

21900872 is a wasteful number, since it uses less digits than its factorization.

21900872 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 270 (or 266 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 29.

The square root of 21900872 is about 4679.8367492894. The cubic root of 21900872 is about 279.7824500629.

The spelling of 21900872 in words is "twenty-one million, nine hundred thousand, eight hundred seventy-two".