The int data type is the default data type for this statement. The default could just as well have been bigint. If I use, or even anticipate using, power(2,31) I obviously intended the statement to handle it and would have typed any resultant variable or table to handle it. I guess I'm mostly mystified by an error statement that returns an error AND the correct answer at the same time. It almost seems like a programmer was trying to have a little fun.
Anyway, I apprecaite your point of view. The long and short of it is whether I get an error at Power(2,31) or if it didn't give me the error and I used the result sometime later in an int datatype, I would have gotten an error either way.