46 Driver,
You are astute! The 53E has a disk loading of about 14 lbs/ft2, and it comes down at about 2800 feet per minute!
It does have a pretty good flare, and lots of rotor inertia, so it can autorotate. One of the old time Sikorsky test pilots, a real pro and former Marine named Jack Peterson, autorotated the 53E during its initial trials back in the mid 1970's. he made a soft landing a about 25 to 30 knots as I recall.