686385569 has 2 divisors, whose sum is σ = 686385570. Its totient is φ = 686385568.

The previous prime is 686385559. The next prime is 686385571. The reversal of 686385569 is 965583686.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 601966225 + 84419344 = 24535^2 + 9188^2 .

It is a cyclic number.

It is not a de Polignac number, because 686385569 - 2⁸ = 686385313 is a prime.

It is a super-2 number, since 2×686385569² = 942250298662907522, which contains 22 as substring.

Together with 686385571, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (686385559) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 343192784 + 343192785.

It is an arithmetic number, because the mean of its divisors is an integer number (343192785).

Almost surely, 2^686385569 is an apocalyptic number.

It is an amenable number.

686385569 is a deficient number, since it is larger than the sum of its proper divisors (1).

686385569 is an equidigital number, since it uses as much as digits as its factorization.

686385569 is an evil number, because the sum of its binary digits is even.

The product of its digits is 9331200, while the sum is 56.

The square root of 686385569 is about 26198.9612198652. The cubic root of 686385569 is about 882.1099374825.

The spelling of 686385569 in words is "six hundred eighty-six million, three hundred eighty-five thousand, five hundred sixty-nine".