Ya its somewhere around 1k and a full cat nuke wont knock it down by more than 1 level.
I rarely use my 1 cat nuke on anyone but me and allies(aka taking a safe province church down to lvl 1) or knocking out extra churches built in a province to protect from Sabos after its over.
Imo, catapults are only usefull on your own churches and cheaper changes of guilds.