21917964 has 24 divisors (see below), whose sum is σ = 54150768. Its totient is φ = 6876160.

The previous prime is 21917927. The next prime is 21917977. The reversal of 21917964 is 46971912.

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, 53517 + ... + 53924.

It is an arithmetic number, because the mean of its divisors is an integer number (2256282).

Almost surely, 2^21917964 is an apocalyptic number.

It is an amenable number.

21917964 is an abundant number, since it is smaller than the sum of its proper divisors (32232804).

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

21917964 is a wasteful number, since it uses less digits than its factorization.

21917964 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 107465 (or 107463 counting only the distinct ones).

The product of its digits is 27216, while the sum is 39.

The square root of 21917964 is about 4681.6625252147. The cubic root of 21917964 is about 279.8552142610.

The spelling of 21917964 in words is "twenty-one million, nine hundred seventeen thousand, nine hundred sixty-four".