21989166566372 has 24 divisors (see below), whose sum is σ = 39134928164640. Its totient is φ = 10808426946240.

The previous prime is 21989166566363. The next prime is 21989166566383. The reversal of 21989166566372 is 27366566198912.

It is a junction number, because it is equal to n+sod(n) for n = 21989166566296 and 21989166566305.

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, 83421497 + ... + 83684672.

It is an arithmetic number, because the mean of its divisors is an integer number (1630622006860).

Almost surely, 2^{21989166566372} is an apocalyptic number.

It is an amenable number.

21989166566372 is a deficient number, since it is larger than the sum of its proper divisors (17145761598268).

21989166566372 is a wasteful number, since it uses less digits than its factorization.

21989166566372 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 167106731 (or 167106729 counting only the distinct ones).

The product of its digits is 352719360, while the sum is 71.

The spelling of 21989166566372 in words is "twenty-one trillion, nine hundred eighty-nine billion, one hundred sixty-six million, five hundred sixty-six thousand, three hundred seventy-two".