幂 originally meant a cloth used to cover ritual vessels, which is why it has the cloth element 巾 at the bottom. Modern Chinese keeps the cover sense in literary use, but the everyday meaning is the mathematical one: a number raised to a power, as in 乘幂 (exponentiation).
The 'cover' radical on top, picturing a cloth draped over something. It is also the sound element, standalone 冖 is read mì, matching the whole character. It indexes 幂 in radical browsing.
The middle block is a contracted shape close to 冥 (dark, hidden). Standalone 冥 has more strokes; here it is squeezed into a seven-stroke residue that reinforces the idea of something covered up and out of sight.
The cloth element at the bottom, standalone 巾 (cloth, towel). It anchors the original meaning of 幂, an actual cloth cover, before the character was borrowed for the mathematical 'power'.
