166158209717 has 2 divisors, whose sum is σ = 166158209718. Its totient is φ = 166158209716.

The previous prime is 166158209681. The next prime is 166158209771. The reversal of 166158209717 is 717902851661.

Together with next prime (166158209771) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 106771444081 + 59386765636 = 326759^2 + 243694^2 .

It is a cyclic number.

It is not a de Polignac number, because 166158209717 - 2²⁰ = 166157161141 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (166158209017) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83079104858 + 83079104859.

It is an arithmetic number, because the mean of its divisors is an integer number (83079104859).

Almost surely, 2^166158209717 is an apocalyptic number.

It is an amenable number.

166158209717 is a deficient number, since it is larger than the sum of its proper divisors (1).

166158209717 is an equidigital number, since it uses as much as digits as its factorization.

166158209717 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1270080, while the sum is 53.

The spelling of 166158209717 in words is "one hundred sixty-six billion, one hundred fifty-eight million, two hundred nine thousand, seven hundred seventeen".