21642493880 has 32 divisors (see below), whose sum is σ = 55652127840. Its totient is φ = 7420283520.

The previous prime is 21642493877. The next prime is 21642493907. The reversal of 21642493880 is 8839424612.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 38647031 + ... + 38647590.

It is an arithmetic number, because the mean of its divisors is an integer number (1739128995).

Almost surely, 2^21642493880 is an apocalyptic number.

21642493880 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21642493880 is an abundant number, since it is smaller than the sum of its proper divisors (34009633960).

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

21642493880 is a wasteful number, since it uses less digits than its factorization.

21642493880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 77294639 (or 77294635 counting only the distinct ones).

The product of its (nonzero) digits is 663552, while the sum is 47.

The spelling of 21642493880 in words is "twenty-one billion, six hundred forty-two million, four hundred ninety-three thousand, eight hundred eighty".