686687 has 2 divisors, whose sum is σ = 686688. Its totient is φ = 686686.

The previous prime is 686671. The next prime is 686723. The reversal of 686687 is 786686.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 686687 - 2⁴ = 686671 is a prime.

It is a Chen prime.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 686687.

It is not a weakly prime, because it can be changed into another prime (686087) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 343343 + 343344.

It is an arithmetic number, because the mean of its divisors is an integer number (343344).

2⁶⁸⁶⁶⁸⁷ is an apocalyptic number.

686687 is a deficient number, since it is larger than the sum of its proper divisors (1).

686687 is an equidigital number, since it uses as much as digits as its factorization.

686687 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 96768, while the sum is 41.

The square root of 686687 is about 828.6657951189. The cubic root of 686687 is about 88.2239046824.

Subtracting 686687 from its reverse (786686), we obtain a palindrome (99999).

The spelling of 686687 in words is "six hundred eighty-six thousand, six hundred eighty-seven".