21839664 has 160 divisors (see below), whose sum is σ = 74280960. Its totient is φ = 5356800.

The previous prime is 21839659. The next prime is 21839677. The reversal of 21839664 is 46693812.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 70069 + ... + 70379.

It is an arithmetic number, because the mean of its divisors is an integer number (464256).

Almost surely, 2^21839664 is an apocalyptic number.

21839664 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 21839664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37140480).

21839664 is an abundant number, since it is smaller than the sum of its proper divisors (52441296).

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

21839664 is a wasteful number, since it uses less digits than its factorization.

21839664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 359 (or 353 counting only the distinct ones).

The product of its digits is 62208, while the sum is 39.

The square root of 21839664 is about 4673.2926293995. The cubic root of 21839664 is about 279.5215639141.

The spelling of 21839664 in words is "twenty-one million, eight hundred thirty-nine thousand, six hundred sixty-four".