686839 has 4 divisors (see below), whose sum is σ = 702856. Its totient is φ = 670824.

The previous prime is 686837. The next prime is 686843. The reversal of 686839 is 938686.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 686839 - 2¹ = 686837 is a prime.

It is a Duffinian number.

686839 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (686837) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7944 + ... + 8029.

It is an arithmetic number, because the mean of its divisors is an integer number (175714).

2⁶⁸⁶⁸³⁹ is an apocalyptic number.

686839 is a deficient number, since it is larger than the sum of its proper divisors (16017).

686839 is a wasteful number, since it uses less digits than its factorization.

686839 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16016.

The product of its digits is 62208, while the sum is 40.

The square root of 686839 is about 828.7575037368. The cubic root of 686839 is about 88.2304137344.

The spelling of 686839 in words is "six hundred eighty-six thousand, eight hundred thirty-nine".