You may be dealing with a caller that could endanger you or your family, so a situation like this is when it would nice to have a free directory where you could easily trace where the call is coming from. Free white pages are available to everyone who uses the web.
This is why you need more information about the cell phone number and this is how reverse cell phone lookup comes in. Before you use reverse white pages to search for your mysterious number, think about they type of number with which you are dealing. Sadly, it appears that these numbers will be protected for a long time to come.
Many of them have this now, and some have had this service for a very long time. This is because while the name might bring up pages of results the telephone number can only be assigned to one name and address and will be much easier to search for. Why waste your time and effort searching on all of these free sites in order to gain nothing?
So make sure you pick a good cell phone directory to find a person by their cell number. Some websites advertise as free, but once you try to search by a cell number, they redirect you to a payment transaction page. Reverse look up of phone number will help you know the location and the identity of your nuisance caller.
Happy searching. I don't think it will be long before you realize just how helpful and speedy they can be.