191863766617 has 2 divisors, whose sum is σ = 191863766618. Its totient is φ = 191863766616.

The previous prime is 191863766609. The next prime is 191863766681. The reversal of 191863766617 is 716667368191.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 179908312336 + 11955454281 = 424156^2 + 109341^2 .

It is an emirp because it is prime and its reverse (716667368191) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 191863766617 - 2³ = 191863766609 is a prime.

It is not a weakly prime, because it can be changed into another prime (191863766417) 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, 95931883308 + 95931883309.

It is an arithmetic number, because the mean of its divisors is an integer number (95931883309).

Almost surely, 2^191863766617 is an apocalyptic number.

It is an amenable number.

191863766617 is a deficient number, since it is larger than the sum of its proper divisors (1).

191863766617 is an equidigital number, since it uses as much as digits as its factorization.

191863766617 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 13716864, while the sum is 61.

The spelling of 191863766617 in words is "one hundred ninety-one billion, eight hundred sixty-three million, seven hundred sixty-six thousand, six hundred seventeen".