21864912 has 40 divisors (see below), whose sum is σ = 56677920. Its totient is φ = 7263360.

The previous prime is 21864893. The next prime is 21864923. The reversal of 21864912 is 21946812.

It is a congruent 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 7 ways as a sum of consecutive naturals, for example, 18087 + ... + 19257.

It is an arithmetic number, because the mean of its divisors is an integer number (1416948).

Almost surely, 2^21864912 is an apocalyptic number.

It is an amenable number.

21864912 is an abundant number, since it is smaller than the sum of its proper divisors (34813008).

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

21864912 is a wasteful number, since it uses less digits than its factorization.

21864912 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1571 (or 1565 counting only the distinct ones).

The product of its digits is 6912, while the sum is 33.

The square root of 21864912 is about 4675.9931565390. The cubic root of 21864912 is about 279.6292371611.

The spelling of 21864912 in words is "twenty-one million, eight hundred sixty-four thousand, nine hundred twelve".