686729 has 2 divisors, whose sum is σ = 686730. Its totient is φ = 686728.

The previous prime is 686723. The next prime is 686731. The reversal of 686729 is 927686.

686729 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 547600 + 139129 = 740^2 + 373^2 .

It is a cyclic number.

It is not a de Polignac number, because 686729 - 2⁸ = 686473 is a prime.

Together with 686731, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 686692 and 686701.

It is not a weakly prime, because it can be changed into another prime (686723) by changing a digit.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 343364 + 343365.

It is an arithmetic number, because the mean of its divisors is an integer number (343365).

2⁶⁸⁶⁷²⁹ is an apocalyptic number.

It is an amenable number.

686729 is a deficient number, since it is larger than the sum of its proper divisors (1).

686729 is an equidigital number, since it uses as much as digits as its factorization.

686729 is an evil number, because the sum of its binary digits is even.

The product of its digits is 36288, while the sum is 38.

The square root of 686729 is about 828.6911366728. The cubic root of 686729 is about 88.2257033323.

The spelling of 686729 in words is "six hundred eighty-six thousand, seven hundred twenty-nine".