191890395197 has 2 divisors, whose sum is σ = 191890395198. Its totient is φ = 191890395196.

The previous prime is 191890395143. The next prime is 191890395241. The reversal of 191890395197 is 791593098191.

191890395197 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 can be written as a sum of positive squares in only one way, i.e., 191138593636 + 751801561 = 437194^2 + 27419^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-191890395197 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (191890395107) 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, 95945197598 + 95945197599.

It is an arithmetic number, because the mean of its divisors is an integer number (95945197599).

Almost surely, 2^191890395197 is an apocalyptic number.

It is an amenable number.

191890395197 is a deficient number, since it is larger than the sum of its proper divisors (1).

191890395197 is an equidigital number, since it uses as much as digits as its factorization.

191890395197 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5511240, while the sum is 62.

The spelling of 191890395197 in words is "one hundred ninety-one billion, eight hundred ninety million, three hundred ninety-five thousand, one hundred ninety-seven".