811138987 has 2 divisors, whose sum is σ = 811138988. Its totient is φ = 811138986.

The previous prime is 811138981. The next prime is 811139009. The reversal of 811138987 is 789831118.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-811138987 is a prime.

It is not a weakly prime, because it can be changed into another prime (811138981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 405569493 + 405569494.

It is an arithmetic number, because the mean of its divisors is an integer number (405569494).

Almost surely, 2^811138987 is an apocalyptic number.

811138987 is a deficient number, since it is larger than the sum of its proper divisors (1).

811138987 is an equidigital number, since it uses as much as digits as its factorization.

811138987 is an evil number, because the sum of its binary digits is even.

The product of its digits is 96768, while the sum is 46.

The square root of 811138987 is about 28480.5018740892. The cubic root of 811138987 is about 932.6064727594.

It can be divided in two parts, 81113 and 8987, that added together give a triangular number (90100 = T₄₂₄).

The spelling of 811138987 in words is "eight hundred eleven million, one hundred thirty-eight thousand, nine hundred eighty-seven".