165217181 has 2 divisors, whose sum is σ = 165217182. Its totient is φ = 165217180.

The previous prime is 165217123. The next prime is 165217189. The reversal of 165217181 is 181712561.

165217181 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., 159012100 + 6205081 = 12610^2 + 2491^2 .

It is a cyclic number.

It is not a de Polignac number, because 165217181 - 2¹⁰ = 165216157 is a prime.

It is a super-2 number, since 2×165217181² = 54593433795173522, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (165217189) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82608590 + 82608591.

It is an arithmetic number, because the mean of its divisors is an integer number (82608591).

Almost surely, 2^165217181 is an apocalyptic number.

It is an amenable number.

165217181 is a deficient number, since it is larger than the sum of its proper divisors (1).

165217181 is an equidigital number, since it uses as much as digits as its factorization.

165217181 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3360, while the sum is 32.

The square root of 165217181 is about 12853.6835576421. The cubic root of 165217181 is about 548.7211953477.

The spelling of 165217181 in words is "one hundred sixty-five million, two hundred seventeen thousand, one hundred eighty-one".