811987 has 8 divisors (see below), whose sum is σ = 896112. Its totient is φ = 729600.

The previous prime is 811981. The next prime is 811991. The reversal of 811987 is 789118.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-811987 is a prime.

It is an Ulam number.

It is a Duffinian number.

811987 is a lucky 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 7 ways as a sum of consecutive naturals, for example, 687 + ... + 1447.

It is an arithmetic number, because the mean of its divisors is an integer number (112014).

2⁸¹¹⁹⁸⁷ is an apocalyptic number.

811987 is a deficient number, since it is larger than the sum of its proper divisors (84125).

811987 is a wasteful number, since it uses less digits than its factorization.

811987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 869.

The product of its digits is 4032, while the sum is 34.

The square root of 811987 is about 901.1032127343. The cubic root of 811987 is about 93.2931360348.

The spelling of 811987 in words is "eight hundred eleven thousand, nine hundred eighty-seven".