191231994659 has 2 divisors, whose sum is σ = 191231994660. Its totient is φ = 191231994658.

The previous prime is 191231994647. The next prime is 191231994697. The reversal of 191231994659 is 956499132191.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 191231994659 - 2²⁰ = 191230946083 is a prime.

It is a Sophie Germain prime.

It is a junction number, because it is equal to n+sod(n) for n = 191231994598 and 191231994607.

It is not a weakly prime, because it can be changed into another prime (191231994559) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 95615997329 + 95615997330.

It is an arithmetic number, because the mean of its divisors is an integer number (95615997330).

Almost surely, 2^191231994659 is an apocalyptic number.

191231994659 is a deficient number, since it is larger than the sum of its proper divisors (1).

191231994659 is an equidigital number, since it uses as much as digits as its factorization.

191231994659 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4723920, while the sum is 59.

The spelling of 191231994659 in words is "one hundred ninety-one billion, two hundred thirty-one million, nine hundred ninety-four thousand, six hundred fifty-nine".