685866 has 8 divisors (see below), whose sum is σ = 1371744. Its totient is φ = 228620.

The previous prime is 685859. The next prime is 685907. The reversal of 685866 is 668586.

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

685866 is an admirable number.

It is an unprimeable number.

685866 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 57150 + ... + 57161.

It is an arithmetic number, because the mean of its divisors is an integer number (171468).

2⁶⁸⁵⁸⁶⁶ is an apocalyptic number.

685866 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

685866 is a wasteful number, since it uses less digits than its factorization.

685866 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 114316.

The product of its digits is 69120, while the sum is 39.

The square root of 685866 is about 828.1702723474. The cubic root of 685866 is about 88.1887306214.

It can be divided in two parts, 685 and 866, that added together give a palindrome (1551).

The spelling of 685866 in words is "six hundred eighty-five thousand, eight hundred sixty-six".