21923664 has 80 divisors (see below), whose sum is σ = 65710080. Its totient is φ = 6168960.

The previous prime is 21923639. The next prime is 21923683. The reversal of 21923664 is 46632912.

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 15 ways as a sum of consecutive naturals, for example, 23397 + ... + 24315.

It is an arithmetic number, because the mean of its divisors is an integer number (821376).

Almost surely, 2^21923664 is an apocalyptic number.

21923664 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21923664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32855040).

21923664 is an abundant number, since it is smaller than the sum of its proper divisors (43786416).

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

21923664 is a wasteful number, since it uses less digits than its factorization.

21923664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1008 (or 1002 counting only the distinct ones).

The product of its digits is 15552, while the sum is 33.

The square root of 21923664 is about 4682.2712437449. The cubic root of 21923664 is about 279.8794719348.

The spelling of 21923664 in words is "twenty-one million, nine hundred twenty-three thousand, six hundred sixty-four".