191128591 has 2 divisors, whose sum is σ = 191128592. Its totient is φ = 191128590.

The previous prime is 191128559. The next prime is 191128601. The reversal of 191128591 is 195821191.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 191128591 - 2⁵ = 191128559 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 191128591.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (191128541) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 95564295 + 95564296.

It is an arithmetic number, because the mean of its divisors is an integer number (95564296).

Almost surely, 2^191128591 is an apocalyptic number.

191128591 is a deficient number, since it is larger than the sum of its proper divisors (1).

191128591 is an equidigital number, since it uses as much as digits as its factorization.

191128591 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6480, while the sum is 37.

The square root of 191128591 is about 13824.9264374173. The cubic root of 191128591 is about 576.0257340853.

The spelling of 191128591 in words is "one hundred ninety-one million, one hundred twenty-eight thousand, five hundred ninety-one".