685291 has 4 divisors (see below), whose sum is σ = 701272. Its totient is φ = 669312.

The previous prime is 685271. The next prime is 685297. The reversal of 685291 is 192586.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 192586 = 2 ⋅96293.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-685291 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (685297) 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, 7926 + ... + 8011.

It is an arithmetic number, because the mean of its divisors is an integer number (175318).

2⁶⁸⁵²⁹¹ is an apocalyptic number.

685291 is a deficient number, since it is larger than the sum of its proper divisors (15981).

685291 is a wasteful number, since it uses less digits than its factorization.

685291 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15980.

The product of its digits is 4320, while the sum is 31.

The square root of 685291 is about 827.8230487248. The cubic root of 685291 is about 88.1640792088.

The spelling of 685291 in words is "six hundred eighty-five thousand, two hundred ninety-one".