165919186943989 has 2 divisors, whose sum is σ = 165919186943990. Its totient is φ = 165919186943988.

The previous prime is 165919186943977. The next prime is 165919186944041. The reversal of 165919186943989 is 989349681919561.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 130804282780900 + 35114904163089 = 11436970^2 + 5925783^2 .

It is an emirp because it is prime and its reverse (989349681919561) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 165919186943989 - 2⁵ = 165919186943957 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (165919186943089) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82959593471994 + 82959593471995.

It is an arithmetic number, because the mean of its divisors is an integer number (82959593471995).

Almost surely, 2^{165919186943989} is an apocalyptic number.

It is an amenable number.

165919186943989 is a deficient number, since it is larger than the sum of its proper divisors (1).

165919186943989 is an equidigital number, since it uses as much as digits as its factorization.

165919186943989 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8162933760, while the sum is 88.

The spelling of 165919186943989 in words is "one hundred sixty-five trillion, nine hundred nineteen billion, one hundred eighty-six million, nine hundred forty-three thousand, nine hundred eighty-nine".