191957981291 has 2 divisors, whose sum is σ = 191957981292. Its totient is φ = 191957981290.

The previous prime is 191957981197. The next prime is 191957981297. The reversal of 191957981291 is 192189759191.

191957981291 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 191957981291 - 2³⁰ = 190884239467 is a prime.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (191957981297) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 95978990645 + 95978990646.

It is an arithmetic number, because the mean of its divisors is an integer number (95978990646).

Almost surely, 2^191957981291 is an apocalyptic number.

191957981291 is a deficient number, since it is larger than the sum of its proper divisors (1).

191957981291 is an equidigital number, since it uses as much as digits as its factorization.

191957981291 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3674160, while the sum is 62.

The spelling of 191957981291 in words is "one hundred ninety-one billion, nine hundred fifty-seven million, nine hundred eighty-one thousand, two hundred ninety-one".