If you don't know anything about a cell phone number, it's best to start with a simple free search to let you know where the number is located, what carrier operates the number, if it's a cell phone or landline number, etc.

2. Search Through Free White Pages Listings

If you've run your free search and found that the number is a landline phone number, run a search at one of the many free reverse landline phone number services on the web.