685391 has 8 divisors (see below), whose sum is σ = 789120. Its totient is φ = 583128.

The previous prime is 685381. The next prime is 685393. The reversal of 685391 is 193586.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a de Polignac number, because none of the positive numbers 2^k-685391 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (685393) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 980 + ... + 1526.

It is an arithmetic number, because the mean of its divisors is an integer number (98640).

2⁶⁸⁵³⁹¹ is an apocalyptic number.

685391 is a deficient number, since it is larger than the sum of its proper divisors (103729).

685391 is a wasteful number, since it uses less digits than its factorization.

685391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 733.

The product of its digits is 6480, while the sum is 32.

The square root of 685391 is about 827.8834459029. The cubic root of 685391 is about 88.1683674012.

The spelling of 685391 in words is "six hundred eighty-five thousand, three hundred ninety-one".