20958317861761 has 10 divisors (see below), whose sum is σ = 24449916008962. Its totient is φ = 17964272450880.

The previous prime is 20958317861699. The next prime is 20958317861779. The reversal of 20958317861761 is 16716871385902.

It can be written as a sum of positive squares in only one way, i.e., 14872939337025 + 6085378524736 = 3856545^2 + 2466856^2 .

It is not a de Polignac number, because 20958317861761 - 2²¹ = 20958315764609 is a prime.

It is a super-2 number, since 2×20958317861761² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20958317861693 and 20958317861702.

It is not an unprimeable number, because it can be changed into a prime (20958317861161) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 4364495280 + ... + 4364500081.

Almost surely, 2^{20958317861761} is an apocalyptic number.

It is an amenable number.

20958317861761 is a deficient number, since it is larger than the sum of its proper divisors (3491598147201).

20958317861761 is an frugal number, since it uses more digits than its factorization.

20958317861761 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8728995389 (or 8728995368 counting only the distinct ones).

The product of its (nonzero) digits is 30481920, while the sum is 64.

The spelling of 20958317861761 in words is "twenty trillion, nine hundred fifty-eight billion, three hundred seventeen million, eight hundred sixty-one thousand, seven hundred sixty-one".