811985 has 8 divisors (see below), whose sum is σ = 979776. Its totient is φ = 646000.

The previous prime is 811981. The next prime is 811991. The reversal of 811985 is 589118.

It is a happy number.

811985 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is not a de Polignac number, because 811985 - 2² = 811981 is a prime.

It is a Duffinian number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 811985.

It is not an unprimeable number, because it can be changed into a prime (811981) 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, 932 + ... + 1578.

It is an arithmetic number, because the mean of its divisors is an integer number (122472).

2⁸¹¹⁹⁸⁵ is an apocalyptic number.

It is an amenable number.

811985 is a deficient number, since it is larger than the sum of its proper divisors (167791).

811985 is a wasteful number, since it uses less digits than its factorization.

811985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 903.

The product of its digits is 2880, while the sum is 32.

The square root of 811985 is about 901.1021029828. The cubic root of 811985 is about 93.2930594381.

The spelling of 811985 in words is "eight hundred eleven thousand, nine hundred eighty-five".