PrimeChecker

public class PrimeChecker {

    // Function to check if a number is prime
    public static boolean isPrime(int number) {
        if (number <= 1) {
            return false; // Numbers less than or equal to 1 are not prime
        }
        if (number <= 3) {
            return true; // 2 and 3 are prime numbers
        }
        if (number % 2 == 0 || number % 3 == 0) {
            return false; // Divisible by 2 or 3, not prime
        }
        
        // Check for prime by testing divisors up to the square root of the number
        for (int i = 5; i * i <= number; i += 6) {
            if (number % i == 0 || number % (i + 2) == 0) {
                return false;
            }
        }
        
        return true; // If no divisors found, the number is prime
    }

    public static void main(String[] args) {
        int number = 17; // Change this number to check if it's prime
        
        if (isPrime(number)) {
            System.out.println(number + " is a prime number.");
        } else {
            System.out.println(number + " is not a prime number.");
        }
    }
}