686365657 has 2 divisors, whose sum is σ = 686365658. Its totient is φ = 686365656.

The previous prime is 686365643. The next prime is 686365661. The reversal of 686365657 is 756563686.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 364199056 + 322166601 = 19084^2 + 17949^2 .

It is a cyclic number.

It is not a de Polignac number, because 686365657 - 2¹⁹ = 685841369 is a prime.

It is not a weakly prime, because it can be changed into another prime (686365607) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 343182828 + 343182829.

It is an arithmetic number, because the mean of its divisors is an integer number (343182829).

Almost surely, 2^686365657 is an apocalyptic number.

It is an amenable number.

686365657 is a deficient number, since it is larger than the sum of its proper divisors (1).

686365657 is an equidigital number, since it uses as much as digits as its factorization.

686365657 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5443200, while the sum is 52.

The square root of 686365657 is about 26198.5812020422. The cubic root of 686365657 is about 882.1014074164.

The spelling of 686365657 in words is "six hundred eighty-six million, three hundred sixty-five thousand, six hundred fifty-seven".