Sure, is it safe to display the number on the back? I wouldn't see why not, just want to clarify.
No! Not if it's the number of the beast. The gates of hell could be wide opened... The world would be headed for a disaster of biblical proportions. Fire and brimstone coming down from the sky! Rivers and seas boiling! Forty years of darkness! Earthquakes, volcanoes! The dead rising from the grave! Human sacrifice! Dogs and cats, living together! Mass hysteria!
If it's not the number of the beast, then go ahead... It's safe.