Is this led bulb able to be replaced when it burns out?
No,the led bulb can not be replaced.
Is the gooseneck flexible enough to reverse the lighting direction?
Yes, the neck is fully flexible and the light head can spin to any direction.
What kind of bulb does it take?
It's built-in LED light, the bulb can not be replaced.
What kind of plug? Three prong or 2?
The plug is 2 prong plug in and operates on a USB cord.