Yes this number is from 911 operator.
Last night I accidentally called 911 last night and this number called me so I anwsered it it said "You called 911 recently " and I said it was an accident so they asked me couple questions then I was free to go. Remember don't hang up like I did when you accidentally call 911 don't hang up if you dothey will call you back and if you missed it they will send police, ambulance and firetrucks to your house.
So don't play with 911 calls

I just experienced this and I had not used my cell phone all evening. they called 2x and said it was CPS returning my phone call because I had dialed 911. Weird, maybe my phone is a defect.

Same as above.  I was suspicious and tried to call back when my phone log didn't show any 911 call going out.  Automated message says that number doesn't exist.  Tired turning off my phone.  Phone is locked on, ie they continue to listen to your phone even after they have hung up.   It felt a bit creepy so I pulled the battery.   Phone was fine after.   You could turn it on and off.  If you can't it means they've locked you phone line open so they can verify if there really is an emergency.  My daughter was  putting her children to bed at the time and that's always a sob time.  Perhaps they heard that in the background and decided to keep the line open in case.  

Just got two calls from this number on my cell this afternoon.  It went to voice mail and a female voice said it was 911 calling - that my cell had called them and to stay on the line if I needed help.  According to my call log its total BS.  This is either a collector going to previously unheard of nastiness or a real a***ole scammer.

This number is genuinely from 911 emergency. Some cell phones do not store 911 calls in their call logs so be carefully with the emergency call buttons (i.e., blackberry lock screen)

This number was left on our answering machine. Due to privacy reasons, cannot return call.

Yup this is CPS, I was actually trying to call 911 today (car accident) but my silly cell kept picking up my Bluetooth in my other car LOL (I was less than a block from my house) I eventually got through ok but they had called to see why I was calling 911.