686609 has 16 divisors (see below), whose sum is σ = 882816. Its totient is φ = 518400.

The previous prime is 686593. The next prime is 686611. The reversal of 686609 is 906686.

It is a cyclic number.

It is not a de Polignac number, because 686609 - 2⁴ = 686593 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (686639) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2729 + ... + 2969.

It is an arithmetic number, because the mean of its divisors is an integer number (55176).

2⁶⁸⁶⁶⁰⁹ is an apocalyptic number.

It is an amenable number.

686609 is a deficient number, since it is larger than the sum of its proper divisors (196207).

686609 is a wasteful number, since it uses less digits than its factorization.

686609 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 296.

The product of its (nonzero) digits is 15552, while the sum is 35.

The square root of 686609 is about 828.6187301769. The cubic root of 686609 is about 88.2205641381.

The spelling of 686609 in words is "six hundred eighty-six thousand, six hundred nine".