21866764 has 6 divisors (see below), whose sum is σ = 38266844. Its totient is φ = 10933380.

The previous prime is 21866753. The next prime is 21866773. The reversal of 21866764 is 46766812.

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 as a sum of consecutive naturals, namely, 2733342 + ... + 2733349.

Almost surely, 2^21866764 is an apocalyptic number.

It is an amenable number.

21866764 is a deficient number, since it is larger than the sum of its proper divisors (16400080).

21866764 is a wasteful number, since it uses less digits than its factorization.

21866764 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5466695 (or 5466693 counting only the distinct ones).

The product of its digits is 96768, while the sum is 40.

The square root of 21866764 is about 4676.1911851420. The cubic root of 21866764 is about 279.6371319825.

The spelling of 21866764 in words is "twenty-one million, eight hundred sixty-six thousand, seven hundred sixty-four".