21977164 has 12 divisors (see below), whose sum is σ = 41956488. Its totient is φ = 9989600.

The previous prime is 21977159. The next prime is 21977177. The reversal of 21977164 is 46177912.

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, 249697 + ... + 249784.

It is an arithmetic number, because the mean of its divisors is an integer number (3496374).

Almost surely, 2^21977164 is an apocalyptic number.

It is an amenable number.

21977164 is a deficient number, since it is larger than the sum of its proper divisors (19979324).

21977164 is a wasteful number, since it uses less digits than its factorization.

21977164 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 499496 (or 499494 counting only the distinct ones).

The product of its digits is 21168, while the sum is 37.

The square root of 21977164 is about 4687.9808020085. The cubic root of 21977164 is about 280.1069489404.

The spelling of 21977164 in words is "twenty-one million, nine hundred seventy-seven thousand, one hundred sixty-four".