305609 has 4 divisors (see below), whose sum is σ = 323604. Its totient is φ = 287616.

The previous prime is 305603. The next prime is 305611. The reversal of 305609 is 906503.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 198025 + 107584 = 445^2 + 328^2 .

It is a cyclic number.

It is not a de Polignac number, because 305609 - 2⁴ = 305593 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (305603) 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, 8972 + ... + 9005.

It is an arithmetic number, because the mean of its divisors is an integer number (80901).

2³⁰⁵⁶⁰⁹ is an apocalyptic number.

It is an amenable number.

305609 is a deficient number, since it is larger than the sum of its proper divisors (17995).

305609 is a wasteful number, since it uses less digits than its factorization.

305609 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17994.

The product of its (nonzero) digits is 810, while the sum is 23.

The square root of 305609 is about 552.8191385978. The cubic root of 305609 is about 67.3579270571.

It can be divided in two parts, 305 and 609, that multiplied together give a triangular number (185745 = T₆₀₉).

The spelling of 305609 in words is "three hundred five thousand, six hundred nine".