21658770668472 has 48 divisors (see below), whose sum is σ = 62987241233160. Its totient is φ = 6188220190656.

The previous prime is 21658770668443. The next prime is 21658770668477. The reversal of 21658770668472 is 27486607785612.

It is a junction number, because it is equal to n+sod(n) for n = 21658770668397 and 21658770668406.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21658770668477) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 9208659823 + ... + 9208662174.

Almost surely, 2^{21658770668472} is an apocalyptic number.

It is an amenable number.

21658770668472 is an abundant number, since it is smaller than the sum of its proper divisors (41328470564688).

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

21658770668472 is a wasteful number, since it uses less digits than its factorization.

21658770668472 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18417322020 (or 18417322009 counting only the distinct ones).

The product of its (nonzero) digits is 379330560, while the sum is 69.

The spelling of 21658770668472 in words is "twenty-one trillion, six hundred fifty-eight billion, seven hundred seventy million, six hundred sixty-eight thousand, four hundred seventy-two".