165665511181 has 2 divisors, whose sum is σ = 165665511182. Its totient is φ = 165665511180.

The previous prime is 165665511149. The next prime is 165665511197. The reversal of 165665511181 is 181115566561.

165665511181 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 87226306281 + 78439204900 = 295341^2 + 280070^2 .

It is a cyclic number.

It is not a de Polignac number, because 165665511181 - 2⁵ = 165665511149 is a prime.

It is a super-2 number, since 2×165665511181² (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 (165665511101) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82832755590 + 82832755591.

It is an arithmetic number, because the mean of its divisors is an integer number (82832755591).

Almost surely, 2^165665511181 is an apocalyptic number.

It is an amenable number.

165665511181 is a deficient number, since it is larger than the sum of its proper divisors (1).

165665511181 is an equidigital number, since it uses as much as digits as its factorization.

165665511181 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 216000, while the sum is 46.

The spelling of 165665511181 in words is "one hundred sixty-five billion, six hundred sixty-five million, five hundred eleven thousand, one hundred eighty-one".