180409 has 4 divisors (see below), whose sum is σ = 186660. Its totient is φ = 174160.

The previous prime is 180391. The next prime is 180413. The reversal of 180409 is 904081.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 904081 = 61 ⋅14821.

It can be written as a sum of positive squares in 2 ways, for example, as 42025 + 138384 = 205^2 + 372^2 .

It is a cyclic number.

It is not a de Polignac number, because 180409 - 2⁷ = 180281 is a prime.

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 180409.

It is not an unprimeable number, because it can be changed into a prime (180419) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3082 + ... + 3139.

It is an arithmetic number, because the mean of its divisors is an integer number (46665).

2¹⁸⁰⁴⁰⁹ is an apocalyptic number.

It is an amenable number.

180409 is a deficient number, since it is larger than the sum of its proper divisors (6251).

180409 is an equidigital number, since it uses as much as digits as its factorization.

180409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6250.

The product of its (nonzero) digits is 288, while the sum is 22.

The square root of 180409 is about 424.7458063360. The cubic root of 180409 is about 56.5048942428.

The spelling of 180409 in words is "one hundred eighty thousand, four hundred nine".