811121791 has 2 divisors, whose sum is σ = 811121792. Its totient is φ = 811121790.

The previous prime is 811121783. The next prime is 811121803. The reversal of 811121791 is 197121118.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 811121791 - 2³ = 811121783 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (811121711) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 405560895 + 405560896.

It is an arithmetic number, because the mean of its divisors is an integer number (405560896).

Almost surely, 2^811121791 is an apocalyptic number.

811121791 is a deficient number, since it is larger than the sum of its proper divisors (1).

811121791 is an equidigital number, since it uses as much as digits as its factorization.

811121791 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1008, while the sum is 31.

The square root of 811121791 is about 28480.1999817417. The cubic root of 811121791 is about 932.5998823499.

The spelling of 811121791 in words is "eight hundred eleven million, one hundred twenty-one thousand, seven hundred ninety-one".