687839 has 2 divisors, whose sum is σ = 687840. Its totient is φ = 687838.

The previous prime is 687829. The next prime is 687847. The reversal of 687839 is 938786.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 687839 - 2⁴ = 687823 is a prime.

It is a Sophie Germain prime.

It is a junction number, because it is equal to n+sod(n) for n = 687796 and 687805.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (687809) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 343919 + 343920.

It is an arithmetic number, because the mean of its divisors is an integer number (343920).

2⁶⁸⁷⁸³⁹ is an apocalyptic number.

687839 is a deficient number, since it is larger than the sum of its proper divisors (1).

687839 is an equidigital number, since it uses as much as digits as its factorization.

687839 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 72576, while the sum is 41.

The square root of 687839 is about 829.3605970867. The cubic root of 687839 is about 88.2732125217.

The spelling of 687839 in words is "six hundred eighty-seven thousand, eight hundred thirty-nine".