How to use the square root to help determine if a number is prime?

Question:

How to use the square root to help determine if a number is prime?

Code:

import java.util.*;
public class CheckPrime {
  public static void main(String[] args) {
 
    Scanner input = new Scanner(System.in);
 
    System.out.print("Enter a number: ");
    Double number = input.nextDouble();
 
    boolean prime = true;
 
    int sqrt = (int) Math.sqrt(number) + 1;
    for (int i = 2; i < sqrt; i++) {
      if (number%i == 0) {
        prime=false;
        break;
      }
    }
 
    if (prime == false) {
      System.out.println("The number that you entered is not prime");
    } else {
      System.out.println("The number that you entered is prime");
    }
  }
}

Output:

$ java CheckPrime
Enter a number: 22
The number that you entered is not prime

$ java CheckPrime
Enter a number: 101
The number that you entered is prime