This number is reportedly a cell number for Suntrust Mortgage Sales rep.  Suntrust Mortgage, after purchasing home loans form smaller banks and financial institutions apparently uses this tactic to call mortgage customers of the loans just purchased to sell them other accounts (checking, savings, etc).  The phone definitely sounds like a cell (or I was on speaker phone) and the caller's message said, this "is not a sales or collections call."  

Take of that what you will.