如何確定一個數爲素數

</pre><pre name="code" class="plain">import java.util.Scanner;


public class Test 
{
	public static void main(String[] args) 
	{
		Scanner input = new Scanner(System.in);
		int number;
		int isPrime=1;
		
		number = input.nextInt();
		for(int i =2;i<=number;i++)
		{
			if(number % i ==0)
			{
				isPrime = 0;
				System.out.println(number+"不是素數");break;
			}
		}
		if(isPrime == 1)
		{
			System.out.println(number+"是素數");
		}
		else
		{
			System.out.println(number+"不是素數");
		}
	}		
}