21931305984 has 352 divisors, whose sum is σ = 75198592000. Its totient is φ = 6261608448.

The previous prime is 21931305967. The next prime is 21931306069. The reversal of 21931305984 is 48950313912.

It is a happy number.

21931305984 is a `hidden beast` number, since 21 + 9 + 3 + 1 + 30 + 598 + 4 = 666.

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, 15675717 + ... + 15677115.

Almost surely, 2^21931305984 is an apocalyptic number.

21931305984 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 21931305984, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37599296000).

21931305984 is an abundant number, since it is smaller than the sum of its proper divisors (53267286016).

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

21931305984 is an frugal number, since it uses more digits than its factorization.

21931305984 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1447 (or 1411 counting only the distinct ones).

The product of its (nonzero) digits is 233280, while the sum is 45.

The spelling of 21931305984 in words is "twenty-one billion, nine hundred thirty-one million, three hundred five thousand, nine hundred eighty-four".