685811 has 4 divisors (see below), whose sum is σ = 783792. Its totient is φ = 587832.

The previous prime is 685793. The next prime is 685819. The reversal of 685811 is 118586.

685811 = 310² + 311² + ... + 316².

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 685811 - 2⁶ = 685747 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 7.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 685811.

It is not an unprimeable number, because it can be changed into a prime (685819) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 48980 + ... + 48993.

It is an arithmetic number, because the mean of its divisors is an integer number (195948).

2⁶⁸⁵⁸¹¹ is an apocalyptic number.

685811 is a deficient number, since it is larger than the sum of its proper divisors (97981).

685811 is an equidigital number, since it uses as much as digits as its factorization.

685811 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 97980.

The product of its digits is 1920, while the sum is 29.

The square root of 685811 is about 828.1370659498. The cubic root of 685811 is about 88.1863732562.

The spelling of 685811 in words is "six hundred eighty-five thousand, eight hundred eleven".