165045409 has 9 divisors (see below), whose sum is σ = 171319603. Its totient is φ = 158994472.

The previous prime is 165045383. The next prime is 165045421. The reversal of 165045409 is 904540561.

The square root of 165045409 is 12847.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 86545809 + 78499600 = 9303^2 + 8860^2 .

It is not a de Polignac number, because 165045409 - 2⁷ = 165045281 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (165045709) 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 in 8 ways as a sum of consecutive naturals, for example, 372342 + ... + 372784.

Almost surely, 2^165045409 is an apocalyptic number.

165045409 is the 12847-th square number.

165045409 is the 6424-th centered octagonal number.

It is an amenable number.

165045409 is a deficient number, since it is larger than the sum of its proper divisors (6274194).

165045409 is an frugal number, since it uses more digits than its factorization.

165045409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 944 (or 472 counting only the distinct ones).

The product of its (nonzero) digits is 21600, while the sum is 34.

The cubic root of 165045409 is about 548.5309656951.

The spelling of 165045409 in words is "one hundred sixty-five million, forty-five thousand, four hundred nine".