21659981832 has 24 divisors (see below), whose sum is σ = 58662450990. Its totient is φ = 7219993920.

The previous prime is 21659981813. The next prime is 21659981867. The reversal of 21659981832 is 23818995612.

21659981832 is a `hidden beast` number, since 2 + 1 + 6 + 599 + 8 + 18 + 32 = 666.

It can be written as a sum of positive squares in only one way, i.e., 14513984676 + 7145997156 = 120474^2 + 84534^2 .

It is a tau number, because it is divible by the number of its divisors (24).

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 150416469 + ... + 150416612.

Almost surely, 2^21659981832 is an apocalyptic number.

It is an amenable number.

21659981832 is an abundant number, since it is smaller than the sum of its proper divisors (37002469158).

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

21659981832 is a wasteful number, since it uses less digits than its factorization.

21659981832 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 300833093 (or 300833086 counting only the distinct ones).

The product of its digits is 1866240, while the sum is 54.

The spelling of 21659981832 in words is "twenty-one billion, six hundred fifty-nine million, nine hundred eighty-one thousand, eight hundred thirty-two".