I've always wondered about this, does an idling prob actually produce more drag than a stationary one...especially if its three bladed?
Contacttower, unless there is a massive internal failure (a broken crankshaft for instance), don't expect the prop to be stationary. It will be windmilling, and a windmilling prop will cause more drag than a prop that's running at idle. After all, at idle there's at least a minimum amount of fuel going into the cylinders helping the prop tick over.
What I've heard is that a stationary prop will cause less drag than a windmilling one, but in order to get the prop really stopped you've got to slow down to something very close to stall speed, usually. That's not something you're going to do with an engine failure, unless you've got steel nerves and plenty altitude to spare.
I'm flying aerobatics, including negative g manoeuvres, in an aircraft without an inverted flight system. So far I haven't been in the situation where the prop actually stopped, but one of these days I'm going to take the aircraft up high and deliberately find out at what speed the prop stops windmilling, and what speed is required to get it going again.