811685 has 12 divisors (see below), whose sum is σ = 1133388. Its totient is φ = 556416.

The previous prime is 811667. The next prime is 811691. The reversal of 811685 is 586118.

811685 = 38² + 39² + ... + 135².

It can be written as a sum of positive squares in 2 ways, for example, as 550564 + 261121 = 742^2 + 511^2 .

It is not a de Polignac number, because 811685 - 2⁸ = 811429 is a prime.

It is a Smith number, since the sum of its digits (29) coincides with the sum of the digits of its prime factors.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1412 + ... + 1901.

It is an arithmetic number, because the mean of its divisors is an integer number (94449).

2⁸¹¹⁶⁸⁵ is an apocalyptic number.

It is an amenable number.

811685 is a deficient number, since it is larger than the sum of its proper divisors (321703).

811685 is a wasteful number, since it uses less digits than its factorization.

811685 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3332 (or 3325 counting only the distinct ones).

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

The square root of 811685 is about 900.9356247813. The cubic root of 811685 is about 93.2815685176.

The spelling of 811685 in words is "eight hundred eleven thousand, six hundred eighty-five".