165798181 has 2 divisors, whose sum is σ = 165798182. Its totient is φ = 165798180.

The previous prime is 165798163. The next prime is 165798197. The reversal of 165798181 is 181897561.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 144720900 + 21077281 = 12030^2 + 4591^2 .

It is a cyclic number.

It is not a de Polignac number, because 165798181 - 2²⁷ = 31580453 is a prime.

It is a super-2 number, since 2×165798181² = 54978073645817522, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (165798121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82899090 + 82899091.

It is an arithmetic number, because the mean of its divisors is an integer number (82899091).

Almost surely, 2^165798181 is an apocalyptic number.

It is an amenable number.

165798181 is a deficient number, since it is larger than the sum of its proper divisors (1).

165798181 is an equidigital number, since it uses as much as digits as its factorization.

165798181 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 120960, while the sum is 46.

The square root of 165798181 is about 12876.2642486088. The cubic root of 165798181 is about 549.3636508057.

The spelling of 165798181 in words is "one hundred sixty-five million, seven hundred ninety-eight thousand, one hundred eighty-one".