iTunes and voice memos

What you see in the iTunes window does not necessarily have anything to do with the actual file name. I believe voice memos having numbers as names is standard. Once you have the memo copied out of iTunes you can re-name it as you would any file. There are ways to re-name it inside of iTunes but that can mess with the interface and I wouldn't do it unless you are answering questions here instead of asking them. 😉

The files were not named in iTunes. What you see in iTunes are tags which are labels stored inside each audio file.

http://dougscripts.com/itunes/scripts/ss.php?sp=filerenamer

So you made a mistake in not realizing what you were doing wasn't renaming your actual files. Now you have learned something. Use the tool I linked to remedy your mistake.