191940050021 has 2 divisors, whose sum is σ = 191940050022. Its totient is φ = 191940050020.

The previous prime is 191940049937. The next prime is 191940050023. The reversal of 191940050021 is 120050049191.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 96404040100 + 95536009921 = 310490^2 + 309089^2 .

It is an emirp because it is prime and its reverse (120050049191) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-191940050021 is a prime.

Together with 191940050023, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 191940050021.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (191940050023) 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, 95970025010 + 95970025011.

It is an arithmetic number, because the mean of its divisors is an integer number (95970025011).

Almost surely, 2^191940050021 is an apocalyptic number.

It is an amenable number.

191940050021 is a deficient number, since it is larger than the sum of its proper divisors (1).

191940050021 is an equidigital number, since it uses as much as digits as its factorization.

191940050021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3240, while the sum is 32.

The spelling of 191940050021 in words is "one hundred ninety-one billion, nine hundred forty million, fifty thousand, twenty-one".