GEOMEAN(b1, b2, ...)
GEOMEAN returns the geometric mean of the given arguments. This is equal to the Nth root of the product of the terms.
Let us assume that the cells A1, A2, ..., A5 contain numbers 11.4, 17.3, 21.3, 25.9, and 40.1. Then
GEOMEAN(A1:A5) equals 21.279182482.