171108816509 has 2 divisors, whose sum is σ = 171108816510. Its totient is φ = 171108816508.

The previous prime is 171108816479. The next prime is 171108816523. The reversal of 171108816509 is 905618801171.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 171108804409 + 12100 = 413653^2 + 110^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-171108816509 is a prime.

It is a super-2 number, since 2×171108816509² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (171108816589) 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, 85554408254 + 85554408255.

It is an arithmetic number, because the mean of its divisors is an integer number (85554408255).

Almost surely, 2^171108816509 is an apocalyptic number.

It is an amenable number.

171108816509 is a deficient number, since it is larger than the sum of its proper divisors (1).

171108816509 is an equidigital number, since it uses as much as digits as its factorization.

171108816509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 120960, while the sum is 47.

The spelling of 171108816509 in words is "one hundred seventy-one billion, one hundred eight million, eight hundred sixteen thousand, five hundred nine".