686816659 has 2 divisors, whose sum is σ = 686816660. Its totient is φ = 686816658.

The previous prime is 686816651. The next prime is 686816719. The reversal of 686816659 is 956618686.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 686816659 - 2³ = 686816651 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (686816651) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 343408329 + 343408330.

It is an arithmetic number, because the mean of its divisors is an integer number (343408330).

Almost surely, 2^686816659 is an apocalyptic number.

686816659 is a deficient number, since it is larger than the sum of its proper divisors (1).

686816659 is an equidigital number, since it uses as much as digits as its factorization.

686816659 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3732480, while the sum is 55.

The square root of 686816659 is about 26207.1871630665. The cubic root of 686816659 is about 882.2945709245.

The spelling of 686816659 in words is "six hundred eighty-six million, eight hundred sixteen thousand, six hundred fifty-nine".