165404909 has 2 divisors, whose sum is σ = 165404910. Its totient is φ = 165404908.

The previous prime is 165404887. The next prime is 165404957. The reversal of 165404909 is 909404561.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 84584809 + 80820100 = 9197^2 + 8990^2 .

It is a cyclic number.

It is not a de Polignac number, because 165404909 - 2¹² = 165400813 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (165404959) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82702454 + 82702455.

It is an arithmetic number, because the mean of its divisors is an integer number (82702455).

Almost surely, 2^165404909 is an apocalyptic number.

It is an amenable number.

165404909 is a deficient number, since it is larger than the sum of its proper divisors (1).

165404909 is an equidigital number, since it uses as much as digits as its factorization.

165404909 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 38880, while the sum is 38.

The square root of 165404909 is about 12860.9839825730. The cubic root of 165404909 is about 548.9289448110.

The spelling of 165404909 in words is "one hundred sixty-five million, four hundred four thousand, nine hundred nine".