686979591671 has 2 divisors, whose sum is σ = 686979591672. Its totient is φ = 686979591670.

The previous prime is 686979591643. The next prime is 686979591797. The reversal of 686979591671 is 176195979686.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-686979591671 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (686979591071) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 343489795835 + 343489795836.

It is an arithmetic number, because the mean of its divisors is an integer number (343489795836).

Almost surely, 2^686979591671 is an apocalyptic number.

686979591671 is a deficient number, since it is larger than the sum of its proper divisors (1).

686979591671 is an equidigital number, since it uses as much as digits as its factorization.

686979591671 is an odious number, because the sum of its binary digits is odd.

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

The spelling of 686979591671 in words is "six hundred eighty-six billion, nine hundred seventy-nine million, five hundred ninety-one thousand, six hundred seventy-one".