191693690977 has 2 divisors, whose sum is σ = 191693690978. Its totient is φ = 191693690976.

The previous prime is 191693690953. The next prime is 191693690983. The reversal of 191693690977 is 779096396191.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 170787133696 + 20906557281 = 413264^2 + 144591^2 .

It is an emirp because it is prime and its reverse (779096396191) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 191693690977 - 2¹¹ = 191693688929 is a prime.

It is not a weakly prime, because it can be changed into another prime (191693690477) 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, 95846845488 + 95846845489.

It is an arithmetic number, because the mean of its divisors is an integer number (95846845489).

Almost surely, 2^191693690977 is an apocalyptic number.

It is an amenable number.

191693690977 is a deficient number, since it is larger than the sum of its proper divisors (1).

191693690977 is an equidigital number, since it uses as much as digits as its factorization.

191693690977 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 34720812, while the sum is 67.

The spelling of 191693690977 in words is "one hundred ninety-one billion, six hundred ninety-three million, six hundred ninety thousand, nine hundred seventy-seven".