Who called from 3479976496

like to find out if this is a legit number

You can do a reverse lookup.  Here's a good article on how to do it:

http://www.cbsnews.com/news/reverse-cell-phon ... ree-and-simple/

Most reverse lookup services will give you basic information (location, provider, etc) for free, and detailed info for an additional fee.  I wouldn't bother with any paid options, since it's likely the number is being spoofed, and the true owner is not the one who is calling you.