686439 has 12 divisors (see below), whose sum is σ = 1067976. Its totient is φ = 422352.

The previous prime is 686437. The next prime is 686449. The reversal of 686439 is 934686.

686439 is a `hidden beast` number, since 6 + 8 + 643 + 9 = 666.

It is not a de Polignac number, because 686439 - 2¹ = 686437 is a prime.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (686437) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2817 + ... + 3050.

It is an arithmetic number, because the mean of its divisors is an integer number (88998).

2⁶⁸⁶⁴³⁹ is an apocalyptic number.

686439 is a deficient number, since it is larger than the sum of its proper divisors (381537).

686439 is a wasteful number, since it uses less digits than its factorization.

686439 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5886 (or 5883 counting only the distinct ones).

The product of its digits is 31104, while the sum is 36.

The square root of 686439 is about 828.5161434758. The cubic root of 686439 is about 88.2132825878.

It can be divided in two parts, 6864 and 39, that added together give a triangular number (6903 = T₁₁₇).

The spelling of 686439 in words is "six hundred eighty-six thousand, four hundred thirty-nine".