686696617 has 2 divisors, whose sum is σ = 686696618. Its totient is φ = 686696616.

The previous prime is 686696609. The next prime is 686696639. The reversal of 686696617 is 716696686.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 534025881 + 152670736 = 23109^2 + 12356^2 .

It is a cyclic number.

It is not a de Polignac number, because 686696617 - 2³ = 686696609 is a prime.

It is not a weakly prime, because it can be changed into another prime (686691617) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 343348308 + 343348309.

It is an arithmetic number, because the mean of its divisors is an integer number (343348309).

Almost surely, 2^686696617 is an apocalyptic number.

It is an amenable number.

686696617 is a deficient number, since it is larger than the sum of its proper divisors (1).

686696617 is an equidigital number, since it uses as much as digits as its factorization.

686696617 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3919104, while the sum is 55.

The square root of 686696617 is about 26204.8968133820. The cubic root of 686696617 is about 882.2431653689.

The spelling of 686696617 in words is "six hundred eighty-six million, six hundred ninety-six thousand, six hundred seventeen".