21881325664 has 24 divisors (see below), whose sum is σ = 46995120648. Its totient is φ = 9946056960.

The previous prime is 21881325611. The next prime is 21881325673. The reversal of 21881325664 is 46652318812.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 31081077 + ... + 31081780.

It is an arithmetic number, because the mean of its divisors is an integer number (1958130027).

Almost surely, 2^21881325664 is an apocalyptic number.

It is an amenable number.

21881325664 is an abundant number, since it is smaller than the sum of its proper divisors (25113794984).

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

21881325664 is a wasteful number, since it uses less digits than its factorization.

21881325664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 62162878 (or 62162870 counting only the distinct ones).

The product of its digits is 552960, while the sum is 46.

The spelling of 21881325664 in words is "twenty-one billion, eight hundred eighty-one million, three hundred twenty-five thousand, six hundred sixty-four".