If it is a mobile number, you could put it in the search box on Facebook or other social networking sites which have a mobile feature. Unless it's not public or they haven't linked their mobile with their page, their profile will come up in the results of the mobile number.
I tried to find a number and all the websites don't accept mobile numbers. I searched the whole web and never found it, one even said it didn't exist but I was called by it the day before! the websites just don't find mobile numbers so I stopped trying and I didn't call it cause I didn't know who it was. All I knew was it was English!
Reverse phone look up sites. This is the best possible solution for your problem. I cannot think of any other solutions aside from this. I suggest you try to look up on the web or visit http://www.callnumbersearch.com to learn about this.