21658770668478 has 48 divisors (see below), whose sum is σ = 44864128301616. Its totient is φ = 6970425745920.

The previous prime is 21658770668477. The next prime is 21658770668489. The reversal of 21658770668478 is 87486607785612.

It is a Curzon number.

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 23 ways as a sum of consecutive naturals, for example, 313528950 + ... + 313598022.

It is an arithmetic number, because the mean of its divisors is an integer number (934669339617).

Almost surely, 2^{21658770668478} is an apocalyptic number.

21658770668478 is an abundant number, since it is smaller than the sum of its proper divisors (23205357633138).

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

21658770668478 is a wasteful number, since it uses less digits than its factorization.

21658770668478 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 131277 (or 131248 counting only the distinct ones).

The product of its (nonzero) digits is 1517322240, while the sum is 75.

The spelling of 21658770668478 in words is "twenty-one trillion, six hundred fifty-eight billion, seven hundred seventy million, six hundred sixty-eight thousand, four hundred seventy-eight".