[Cub 800]

I have a Cub 800 (hence the screen name) and today while pulling a lawn roller around it started popping, shut it off and discovered that the exhaust pipe had broken off where it exits the cylinder. maybe about 1/8 " sticking out. not enough to get a pipe wrench on. I doubt if this was ever removed.
What is the easiest way to get this stub out? I would prefer not to remove the engine right now. Is the pipe a regular pipe thread? or something special?

I haven't started taking anything apart yet but it is mostly original. I think the stock muffler.

My thought was to get in there with a hacksaw blade and try to cut through what is left of the pipe.

I don't have an oxy/acet torch so that is out. Probably couldn't get it red hot just with mapp gas.

I'm sure this has happened to others, what did you guys do?