811817989 has 2 divisors, whose sum is σ = 811817990. Its totient is φ = 811817988.

The previous prime is 811817977. The next prime is 811818001. The reversal of 811817989 is 989718118.

It is a balanced prime because it is at equal distance from previous prime (811817977) and next prime (811818001).

It can be written as a sum of positive squares in only one way, i.e., 684240964 + 127577025 = 26158^2 + 11295^2 .

It is a cyclic number.

It is not a de Polignac number, because 811817989 - 2⁹ = 811817477 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (811817969) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 405908994 + 405908995.

It is an arithmetic number, because the mean of its divisors is an integer number (405908995).

Almost surely, 2^811817989 is an apocalyptic number.

It is an amenable number.

811817989 is a deficient number, since it is larger than the sum of its proper divisors (1).

811817989 is an equidigital number, since it uses as much as digits as its factorization.

811817989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 290304, while the sum is 52.

The square root of 811817989 is about 28492.4198516026. The cubic root of 811817989 is about 932.8666275366.

The spelling of 811817989 in words is "eight hundred eleven million, eight hundred seventeen thousand, nine hundred eighty-nine".