686621317 has 2 divisors, whose sum is σ = 686621318. Its totient is φ = 686621316.

The previous prime is 686621303. The next prime is 686621357. The reversal of 686621317 is 713126686.

It is a happy number.

It is an a-pointer prime, because the next prime (686621357) can be obtained adding 686621317 to its sum of digits (40).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 682724641 + 3896676 = 26129^2 + 1974^2 .

It is a cyclic number.

It is not a de Polignac number, because 686621317 - 2⁷ = 686621189 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 686621317.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (686621357) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 343310658 + 343310659.

It is an arithmetic number, because the mean of its divisors is an integer number (343310659).

Almost surely, 2^686621317 is an apocalyptic number.

It is an amenable number.

686621317 is a deficient number, since it is larger than the sum of its proper divisors (1).

686621317 is an equidigital number, since it uses as much as digits as its factorization.

686621317 is an evil number, because the sum of its binary digits is even.

The product of its digits is 72576, while the sum is 40.

The square root of 686621317 is about 26203.4600196234. The cubic root of 686621317 is about 882.2109166110.

The spelling of 686621317 in words is "six hundred eighty-six million, six hundred twenty-one thousand, three hundred seventeen".