20646387971688 has 32 divisors (see below), whose sum is σ = 52127019142560. Its totient is φ = 6813989428800.

The previous prime is 20646387971623. The next prime is 20646387971731. The reversal of 20646387971688 is 88617978364602.

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, 4258740970 + ... + 4258745817.

It is an arithmetic number, because the mean of its divisors is an integer number (1628969348205).

Almost surely, 2^{20646387971688} is an apocalyptic number.

It is an amenable number.

20646387971688 is an abundant number, since it is smaller than the sum of its proper divisors (31480631170872).

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

20646387971688 is a wasteful number, since it uses less digits than its factorization.

20646387971688 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8517486897 (or 8517486893 counting only the distinct ones).

The product of its (nonzero) digits is 1170505728, while the sum is 75.

The spelling of 20646387971688 in words is "twenty trillion, six hundred forty-six billion, three hundred eighty-seven million, nine hundred seventy-one thousand, six hundred eighty-eight".