811989 has 12 divisors (see below), whose sum is σ = 1188096. Its totient is φ = 534312.

The previous prime is 811981. The next prime is 811991. The reversal of 811989 is 989118.

It is not a de Polignac number, because 811989 - 2³ = 811981 is a prime.

It is a super-2 number, since 2×811989² = 1318652272242, which contains 22 as substring.

It is an Ulam number.

It is a plaindrome in base 13.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (811981) 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 11 ways as a sum of consecutive naturals, for example, 204 + ... + 1290.

It is an arithmetic number, because the mean of its divisors is an integer number (99008).

2⁸¹¹⁹⁸⁹ is an apocalyptic number.

It is an amenable number.

811989 is a deficient number, since it is larger than the sum of its proper divisors (376107).

811989 is a wasteful number, since it uses less digits than its factorization.

811989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1176 (or 1173 counting only the distinct ones).

The product of its digits is 5184, while the sum is 36.

The square root of 811989 is about 901.1043224844. The cubic root of 811989 is about 93.2932126313.

The spelling of 811989 in words is "eight hundred eleven thousand, nine hundred eighty-nine".