686621357 has 2 divisors, whose sum is σ = 686621358. Its totient is φ = 686621356.

The previous prime is 686621317. The next prime is 686621393. The reversal of 686621357 is 753126686.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 495463081 + 191158276 = 22259^2 + 13826^2 .

It is a cyclic number.

It is not a de Polignac number, because 686621357 - 2⁸ = 686621101 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (686621317) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 343310678 + 343310679.

It is an arithmetic number, because the mean of its divisors is an integer number (343310679).

Almost surely, 2^686621357 is an apocalyptic number.

It is an amenable number.

686621357 is a deficient number, since it is larger than the sum of its proper divisors (1).

686621357 is an equidigital number, since it uses as much as digits as its factorization.

686621357 is an evil number, because the sum of its binary digits is even.

The product of its digits is 362880, while the sum is 44.

The square root of 686621357 is about 26203.4607828813. The cubic root of 686621357 is about 882.2109337425.

The spelling of 686621357 in words is "six hundred eighty-six million, six hundred twenty-one thousand, three hundred fifty-seven".