I'm on the east coast so the call from Mountain View, CA, came in at 1:38 am and thankfully my cell phone was on "Do Not Disturb"; message left was a robo voice claiming to be YouTube returning my call request.  Wasn't my request....blocking contact.

This is a legitimate phone number for Google Customer Service (i.e. if reaching out to Google Customer Service from within Google Pixel phone's Android OS settings, this is the number on the caller ID when Google customer service returns the call).