This is one of the main numbers for Google Voice.  When you use Google Voice, it can route it through this number so it may show up as the number the caller is calling from.  It can also show up on your bill as the number you called when you used Google Voice

We just got a call from this number.

I got 6 calls from this number, no voicemails. Who is this person and why are they trying so darn hard to get me?