191081992901 has 2 divisors, whose sum is σ = 191081992902. Its totient is φ = 191081992900.

The previous prime is 191081992883. The next prime is 191081992949. The reversal of 191081992901 is 109299180191.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 175434484801 + 15647508100 = 418849^2 + 125090^2 .

It is an emirp because it is prime and its reverse (109299180191) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 191081992901 - 2¹⁸ = 191081730757 is a prime.

It is a super-2 number, since 2×191081992901² (a number of 23 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 191081992901.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (191081992991) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 95540996450 + 95540996451.

It is an arithmetic number, because the mean of its divisors is an integer number (95540996451).

Almost surely, 2^191081992901 is an apocalyptic number.

It is an amenable number.

191081992901 is a deficient number, since it is larger than the sum of its proper divisors (1).

191081992901 is an equidigital number, since it uses as much as digits as its factorization.

191081992901 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 104976, while the sum is 50.

The spelling of 191081992901 in words is "one hundred ninety-one billion, eighty-one million, nine hundred ninety-two thousand, nine hundred one".