17991616717 has 2 divisors, whose sum is σ = 17991616718. Its totient is φ = 17991616716.

The previous prime is 17991616703. The next prime is 17991616759. The reversal of 17991616717 is 71761619971.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 9654831081 + 8336785636 = 98259^2 + 91306^2 .

It is a cyclic number.

It is not a de Polignac number, because 17991616717 - 2⁷ = 17991616589 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (17991616777) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8995808358 + 8995808359.

It is an arithmetic number, because the mean of its divisors is an integer number (8995808359).

Almost surely, 2^17991616717 is an apocalyptic number.

It is an amenable number.

17991616717 is a deficient number, since it is larger than the sum of its proper divisors (1).

17991616717 is an equidigital number, since it uses as much as digits as its factorization.

17991616717 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1000188, while the sum is 55.

The spelling of 17991616717 in words is "seventeen billion, nine hundred ninety-one million, six hundred sixteen thousand, seven hundred seventeen".