Rob Christian and Al Fadi say that Muslims brag that it is a miracle that Mohammad was illiterate; ie that he doesn't read or write.  But another meaning to illiterate is the one who came to a people without a book(The Arabs).  Sahih Bukhari #2125 says that Mohammad was a guardian to the illiterate.  Mohammad was not a name but a title (the praised one).  Mohammad real name at birth and until he was forty years of age was Qutham ibn Abed Al Laat, according to the book of" The life of Mohammad " by Muhammad Hasan Haykel ,page 39.  This is according to Muslim sources.