165476509 has 4 divisors (see below), whose sum is σ = 180519840. Its totient is φ = 150433180.

The previous prime is 165476489. The next prime is 165476561. The reversal of 165476509 is 905674561.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 905674561 = 11 ⋅82334051.

It is a cyclic number.

It is not a de Polignac number, because 165476509 - 2⁵ = 165476477 is a prime.

It is an alternating number because its digits alternate between odd and even.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165476309) 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 in 3 ways as a sum of consecutive naturals, for example, 7521649 + ... + 7521670.

It is an arithmetic number, because the mean of its divisors is an integer number (45129960).

Almost surely, 2^165476509 is an apocalyptic number.

It is an amenable number.

165476509 is a deficient number, since it is larger than the sum of its proper divisors (15043331).

165476509 is a wasteful number, since it uses less digits than its factorization.

165476509 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15043330.

The product of its (nonzero) digits is 226800, while the sum is 43.

The square root of 165476509 is about 12863.7672942261. The cubic root of 165476509 is about 549.0081396444.

It can be divided in two parts, 165 and 476509, that added together give a palindrome (476674).

The spelling of 165476509 in words is "one hundred sixty-five million, four hundred seventy-six thousand, five hundred nine".