686979591761 has 4 divisors (see below), whose sum is σ = 723136412400. Its totient is φ = 650822771124.

The previous prime is 686979591671. The next prime is 686979591797. The reversal of 686979591761 is 167195979686.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 167195979686 = 2 ⋅83597989843.

It is a cyclic number.

It is not a de Polignac number, because 686979591761 - 2²² = 686975397457 is a prime.

It is a super-2 number, since 2×686979591761² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (686979591161) 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 3 ways as a sum of consecutive naturals, for example, 18078410291 + ... + 18078410328.

It is an arithmetic number, because the mean of its divisors is an integer number (180784103100).

Almost surely, 2^686979591761 is an apocalyptic number.

It is an amenable number.

686979591761 is a deficient number, since it is larger than the sum of its proper divisors (36156820639).

686979591761 is a wasteful number, since it uses less digits than its factorization.

686979591761 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36156820638.

The product of its digits is 308629440, while the sum is 74.

The spelling of 686979591761 in words is "six hundred eighty-six billion, nine hundred seventy-nine million, five hundred ninety-one thousand, seven hundred sixty-one".