191693639569 has 2 divisors, whose sum is σ = 191693639570. Its totient is φ = 191693639568.

The previous prime is 191693639551. The next prime is 191693639573. The reversal of 191693639569 is 965936396191.

191693639569 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., 184630917969 + 7062721600 = 429687^2 + 84040^2 .

It is a cyclic number.

It is not a de Polignac number, because 191693639569 - 2¹¹ = 191693637521 is a prime.

It is a super-2 number, since 2×191693639569² (a number of 23 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (191693639509) 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, 95846819784 + 95846819785.

It is an arithmetic number, because the mean of its divisors is an integer number (95846819785).

Almost surely, 2^191693639569 is an apocalyptic number.

It is an amenable number.

191693639569 is a deficient number, since it is larger than the sum of its proper divisors (1).

191693639569 is an equidigital number, since it uses as much as digits as its factorization.

191693639569 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 63772920, while the sum is 67.

The spelling of 191693639569 in words is "one hundred ninety-one billion, six hundred ninety-three million, six hundred thirty-nine thousand, five hundred sixty-nine".