Java Program To Check If The Given Number is Prime or Not

public class PrimeNumber {

    public static void main(String[] args) {
        int num = 41;
        boolean isPrimeNumber = isPrime(num);
        if (isPrimeNumber) {
            System.out.println(num + " is a prime number.");
        } else {
            System.out.println(num + " is not a prime number.");
        }
    }

    public static boolean isPrime(int num) {
        if (num <= 1) {
            return false;
        }
        for (int i = 2; i <= Math.sqrt(num); i++) {
            if (num % i == 0) {
                return false;
            }
        }
        return true;
    }
}