21579311616 has 80 divisors (see below), whose sum is σ = 57529428000. Its totient is φ = 7188000768.

The previous prime is 21579311591. The next prime is 21579311623. The reversal of 21579311616 is 61611397512.

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, 2605530 + ... + 2613798.

It is an arithmetic number, because the mean of its divisors is an integer number (719117850).

Almost surely, 2^21579311616 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21579311616, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28764714000).

21579311616 is an abundant number, since it is smaller than the sum of its proper divisors (35950116384).

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

21579311616 is an equidigital number, since it uses as much as digits as its factorization.

21579311616 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9989 (or 9973 counting only the distinct ones).

The product of its digits is 68040, while the sum is 42.

The spelling of 21579311616 in words is "twenty-one billion, five hundred seventy-nine million, three hundred eleven thousand, six hundred sixteen".