Kotlin – Prime Number Program

Prime Number Program in Kotlin

In Kotlin, you can check if given number n is a Prime number or not, by checking if there is any factor in the range of [2, n/2].

To iterate over possible factors, you can use a For loop statement.


In the following program, we write a function isPrime() that takes an integer value, and checks if the given integer value is a Prime number or not. If the given value is a Prime number, then the function returns true, or else, it returns false.

Kotlin Program

fun isPrime(n: Int): Boolean {
    var i = 2
    while (i < n / i) {
        if (n % i == 0) {
            return false
    return true

fun main() {
    val n = 19

    if (isPrime(n)) {
        println("$n is a Prime Number.")
    } else {
        println("$n is not a Prime Number.")


19 is a Prime Number.