Probably the maker's code or a one time owner's initials and year.
39 cents
39^16 = 28,644,003,124,274,380,508,351,361
.39
Most likely an overseas proof or police dept marking.
2.25 x 10-39 = 0.00000000000000000000000000000000000000225
Apple's own Smart Cover for the iPad is AU$39-$69 (neoprene or leather).
It is the power to turn things into gold
The answer is 4.416956719x10 to the power of 39
36
39 = 3x3x3x3x3x3x3x3x3 =19683
36 times 39 = 315 .
5.5 X 10^11