21931904568 has 64 divisors (see below), whose sum is σ = 62884143360. Its totient is φ = 6244102656.

The previous prime is 21931904567. The next prime is 21931904609. The reversal of 21931904568 is 86540913912.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21931904567) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 183105 + ... + 278192.

It is an arithmetic number, because the mean of its divisors is an integer number (982564740).

Almost surely, 2^21931904568 is an apocalyptic number.

21931904568 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

21931904568 is an abundant number, since it is smaller than the sum of its proper divisors (40952238792).

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

21931904568 is a wasteful number, since it uses less digits than its factorization.

21931904568 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 461596 (or 461592 counting only the distinct ones).

The product of its (nonzero) digits is 466560, while the sum is 48.

The spelling of 21931904568 in words is "twenty-one billion, nine hundred thirty-one million, nine hundred four thousand, five hundred sixty-eight".