191690744477 has 2 divisors, whose sum is σ = 191690744478. Its totient is φ = 191690744476.

The previous prime is 191690744449. The next prime is 191690744491. The reversal of 191690744477 is 774447096191.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 129527290201 + 62163454276 = 359899^2 + 249326^2 .

It is an emirp because it is prime and its reverse (774447096191) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-191690744477 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (191690744407) 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, 95845372238 + 95845372239.

It is an arithmetic number, because the mean of its divisors is an integer number (95845372239).

Almost surely, 2^191690744477 is an apocalyptic number.

It is an amenable number.

191690744477 is a deficient number, since it is larger than the sum of its proper divisors (1).

191690744477 is an equidigital number, since it uses as much as digits as its factorization.

191690744477 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 10668672, while the sum is 59.

The spelling of 191690744477 in words is "one hundred ninety-one billion, six hundred ninety million, seven hundred forty-four thousand, four hundred seventy-seven".