21879912 has 16 divisors (see below), whose sum is σ = 54699840. Its totient is φ = 7293296.

The previous prime is 21879899. The next prime is 21879917. The reversal of 21879912 is 21997812.

It is not an unprimeable number, because it can be changed into a prime (21879917) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 455808 + ... + 455855.

It is an arithmetic number, because the mean of its divisors is an integer number (3418740).

Almost surely, 2^21879912 is an apocalyptic number.

It is an amenable number.

21879912 is an abundant number, since it is smaller than the sum of its proper divisors (32819928).

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

21879912 is a wasteful number, since it uses less digits than its factorization.

21879912 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 911672 (or 911668 counting only the distinct ones).

The product of its digits is 18144, while the sum is 39.

The square root of 21879912 is about 4677.5968188804. The cubic root of 21879912 is about 279.6931672873.

It can be divided in two parts, 21879 and 912, that added together give a triangular number (22791 = T₂₁₃).

The spelling of 21879912 in words is "twenty-one million, eight hundred seventy-nine thousand, nine hundred twelve".