165417509 has 2 divisors, whose sum is σ = 165417510. Its totient is φ = 165417508.

The previous prime is 165417407. The next prime is 165417521. The reversal of 165417509 is 905714561.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 165045409 + 372100 = 12847^2 + 610^2 .

It is a cyclic number.

It is not a de Polignac number, because 165417509 - 2⁸ = 165417253 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (165417569) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82708754 + 82708755.

It is an arithmetic number, because the mean of its divisors is an integer number (82708755).

Almost surely, 2^165417509 is an apocalyptic number.

It is an amenable number.

165417509 is a deficient number, since it is larger than the sum of its proper divisors (1).

165417509 is an equidigital number, since it uses as much as digits as its factorization.

165417509 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 37800, while the sum is 38.

The square root of 165417509 is about 12861.4738268987. The cubic root of 165417509 is about 548.9428829888.

The spelling of 165417509 in words is "one hundred sixty-five million, four hundred seventeen thousand, five hundred nine".