How do I remove the number in the red circle on System Preferences icon (Sierra)
MacBook Pro, macOS Sierra (10.12.4)
I'm guessing you just updated your OS to 10.12.4? If so - that red badge is indicating that 2 factor authorization needs an answer. If you click on iCloud you'll see a popup that allows you to set it up or you can click "Not now".
Once you've done that the red badge will disappear.
Look in
System preferences > Notifications
How do I remove the number in the red circle on System Preferences icon (Sierra)