This number called and left no voicemail, so it must not have been very important.  I have been getting a lot of phone calls from numbers from my own prefix.  I would answer them and it would be a telemarketer.  I researched and there is something called SPOOFING that occurs where they can create a fake caller ID number.  They actually take the time to spoof numbers with your prefix assuming that you will be more likely to answer the phone.  It worked for about a week.  Now I NEVER answer a call from my prefix.