separates a number of 5 digits ..

Here's one way of doing that:

using System;

class Digits
{
   static void Main()
   {
      int[] digits = new int[5];
      Console.Write("Enter a 5 digit number : ");
      string input = Console.ReadLine();
      int number = int.Parse(input);
      int i = 4; // counter
      while (number > 0)
      {
         int digit  = number % 10; // extract last digit = remainder after dividing by 10
         digits[i] = digit; // store in array
         number = number / 10; // divide by 10 ready for extracting next digit
         i--; // decrement counter
      } 

      // write the digits back separated by 3 spaces
      foreach(int digit in digits) Console.Write("{0}   ", digit);
      Console.WriteLine();  
      Console.ReadKey();
   }
}

I'll leave it to you to see what happens if you enter more than or fewer than 5 digits :)