I got a call from this number. It's the Medical College of Wisconsin. It was an automated reminder of my doctor's appointment.
My guess is that any calls coming from the Medical College will show up with this number. It may be a reminder for an appointment, their billing department or even someone using one of their phones to call you.
I just dialed 414-456-8701. It is an internal phone from the Medical College of WI. Those phones do not take incoming calls only make outbound. It is usually someone who works there trying to make a personal phone call.