Program for Prime or Not

Source :

using System;
class Prime
{
static void Main()
{
int n,count=0;
Console.Write("Enter a number : ");
n=int.Parse(Console.ReadLine());
for(int i=1;i<=n;i++)
{
if(n%i==0)
count ++;
}
if(count==2)
Console.WriteLine("{0} is Prime number",n);
else
Console.WriteLine("{0} is not Prime number",n);
}
}

Output:
i) Enter a number : 9
9 is not Prime number

ii) Enter a number : 11
11 is  Prime number