165040409 has 4 divisors (see below), whose sum is σ = 165066804. Its totient is φ = 165014016.

The previous prime is 165040391. The next prime is 165040411. The reversal of 165040409 is 904040561.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 121110025 + 43930384 = 11005^2 + 6628^2 .

It is a cyclic number.

It is not a de Polignac number, because 165040409 - 2⁸ = 165040153 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (165040429) 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 3 ways as a sum of consecutive naturals, for example, 2069 + ... + 18285.

It is an arithmetic number, because the mean of its divisors is an integer number (41266701).

Almost surely, 2^165040409 is an apocalyptic number.

It is an amenable number.

165040409 is a deficient number, since it is larger than the sum of its proper divisors (26395).

165040409 is a wasteful number, since it uses less digits than its factorization.

165040409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26394.

The product of its (nonzero) digits is 4320, while the sum is 29.

The square root of 165040409 is about 12846.8054005655. The cubic root of 165040409 is about 548.5254264468.

The spelling of 165040409 in words is "one hundred sixty-five million, forty thousand, four hundred nine".