21877657788 has 72 divisors (see below), whose sum is σ = 60502719312. Its totient is φ = 6132811776.

The previous prime is 21877657759. The next prime is 21877657819. The reversal of 21877657788 is 88775677812.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 319845 + ... + 382172.

It is an arithmetic number, because the mean of its divisors is an integer number (840315546).

Almost surely, 2^21877657788 is an apocalyptic number.

21877657788 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

21877657788 is an abundant number, since it is smaller than the sum of its proper divisors (38625061524).

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

21877657788 is a wasteful number, since it uses less digits than its factorization.

21877657788 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 702091 (or 702082 counting only the distinct ones).

The product of its digits is 73758720, while the sum is 66.

The spelling of 21877657788 in words is "twenty-one billion, eight hundred seventy-seven million, six hundred fifty-seven thousand, seven hundred eighty-eight".