686539 has 6 divisors (see below), whose sum is σ = 798684. Its totient is φ = 588420.

The previous prime is 686519. The next prime is 686551. The reversal of 686539 is 935686.

It is not a de Polignac number, because 686539 - 2⁹ = 686027 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 15.

It is a junction number, because it is equal to n+sod(n) for n = 686498 and 686507.

It is not an unprimeable number, because it can be changed into a prime (686519) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 6957 + ... + 7054.

It is an arithmetic number, because the mean of its divisors is an integer number (133114).

2⁶⁸⁶⁵³⁹ is an apocalyptic number.

686539 is a deficient number, since it is larger than the sum of its proper divisors (112145).

686539 is a wasteful number, since it uses less digits than its factorization.

686539 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14025 (or 14018 counting only the distinct ones).

The product of its digits is 38880, while the sum is 37.

The square root of 686539 is about 828.5764901323. The cubic root of 686539 is about 88.2175659982.

It can be divided in two parts, 686 and 539, that added together give a triangular number (1225 = T₄₉).

The spelling of 686539 in words is "six hundred eighty-six thousand, five hundred thirty-nine".