21869916 has 12 divisors (see below), whose sum is σ = 51029832. Its totient is φ = 7289968.

The previous prime is 21869879. The next prime is 21869951. The reversal of 21869916 is 61996812.

It is a tau number, because it is divible by the number of its divisors (12).

It is a congruent number.

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, 911235 + ... + 911258.

It is an arithmetic number, because the mean of its divisors is an integer number (4252486).

Almost surely, 2^21869916 is an apocalyptic number.

It is an amenable number.

21869916 is an abundant number, since it is smaller than the sum of its proper divisors (29159916).

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

21869916 is a wasteful number, since it uses less digits than its factorization.

21869916 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1822500 (or 1822498 counting only the distinct ones).

The product of its digits is 46656, while the sum is 42.

The square root of 21869916 is about 4676.5281994232. The cubic root of 21869916 is about 279.6505675004.

The spelling of 21869916 in words is "twenty-one million, eight hundred sixty-nine thousand, nine hundred sixteen".