685861 has 4 divisors (see below), whose sum is σ = 748224. Its totient is φ = 623500.

The previous prime is 685859. The next prime is 685907. The reversal of 685861 is 168586.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 685861 - 2¹ = 685859 is a prime.

It is a super-2 number, since 2×685861² = 940810622642, which contains 22 as substring.

It is a Duffinian number.

It is a nialpdrome in base 7.

It is a zygodrome in base 7.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (685361) by changing a digit.

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, 31165 + ... + 31186.

It is an arithmetic number, because the mean of its divisors is an integer number (187056).

2⁶⁸⁵⁸⁶¹ is an apocalyptic number.

It is an amenable number.

685861 is a deficient number, since it is larger than the sum of its proper divisors (62363).

685861 is a wasteful number, since it uses less digits than its factorization.

685861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 62362.

The product of its digits is 11520, while the sum is 34.

The square root of 685861 is about 828.1672536390. The cubic root of 685861 is about 88.1885163207.

It can be divided in two parts, 68 and 5861, that added together give a square (5929 = 77²).

The spelling of 685861 in words is "six hundred eighty-five thousand, eight hundred sixty-one".