If the search yields just a long unmanageable list after entering the entire number with the area code, try putting everything but the area code in quotations, like this: 555 "555 5555". If that still doesn't deliver, you can try getting rid of the area code, replacing it with the state where that code exists (like Mississippi, Texas, AZ, MT - try the full name and the abbreviation), or even the city (search Houston or NYC, for example), if you know that information. If the area code is from Canada, try acell phone number lookup with that information (or search by province, like Alberta).
To skip the legwork and trace the number right away, I recommend two other options: