Here, first we understand that what is prime number,

### Prime Numbers

A prime number is a natural number greater than 1, that is divisible by only two numbers: 1 and itself.

For Example: 2, 3, 5, 7,11,13……..are the prime numbers.

Note: 0 and 1 are not prime numbers. The 2 is the only even prime number because all the other even numbers can be divided by 2.

### Problem:

**Input : ** Enter a number: 17

**Output: ** 17 is a prime number.

### Explanation

This Java program checks if a given number is prime or not. It prompts the user for input, then utilizes a `for` loop to iterate from 2 up to the square root of the number. Within each iteration, it checks if the number is divisible by the current value of `i`. If a divisor is found, it concludes the number is not prime. If no divisors are found, then it’s a prime number.

### Solution:

#### code:

class PrimeNo{ public static void main(String []args){ int num=7; int temp=0; for(int i =2;i<=num-1;i++){ if(num%i==0){ temp=temp+1; } } if(temp==0){ System.out.println(num+" is a prime number"); } else{ System.out.println(num+" is not prime number "); } } }

##### Output:

7 is a prime number

### Approach 2 : By Using Scanner Class :

import java.util.Scanner; // import scanner class class PrimeNo{ public static void main(String []args){ Scanner sc =new Scanner(System.in); // object of scanner class int temp=0; System.out.println("enter any number"); int num = sc.nextInt(); for(int i =2;i<=num-1;i++){ if(num%i==0){ temp=temp+1; } } if(temp==0){ System.out.println(num+" is a prime number"); } else{ System.out.println(num+" is not prime number "); } } }

##### Output:

enter any number 77 77 is not prime number

##### more java programs for practice:

Java Program to Get Input from User

Find the Greatest of the Two Numbers in Java

Addition of two numbers in java