21658679396761 has 16 divisors (see below), whose sum is σ = 23638380439680. Its totient is φ = 19680768123520.

The previous prime is 21658679396759. The next prime is 21658679396771. The reversal of 21658679396761 is 16769397685612.

It is a cyclic number.

It is not a de Polignac number, because 21658679396761 - 2¹ = 21658679396759 is a prime.

It is a super-2 number, since 2×21658679396761² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21658679396771) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 397357836 + ... + 397412338.

It is an arithmetic number, because the mean of its divisors is an integer number (1477398777480).

Almost surely, 2^{21658679396761} is an apocalyptic number.

It is an amenable number.

21658679396761 is a deficient number, since it is larger than the sum of its proper divisors (1979701042919).

21658679396761 is a wasteful number, since it uses less digits than its factorization.

21658679396761 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 70256.

The product of its digits is 1234517760, while the sum is 76.

The spelling of 21658679396761 in words is "twenty-one trillion, six hundred fifty-eight billion, six hundred seventy-nine million, three hundred ninety-six thousand, seven hundred sixty-one".