This expresses the base-10/common logarithm of positive real number 4^16,
since nothing specific is defined on its base.
Using a calculator equipped with common logarithm functions, we have
log4^16 = 16 x log(4) (= 16 x 0.6020599913…) = 9.632959861… ≈ 9.633
or using the x^n key for 4^16, we have
log(4^16) = 9.632959861… ≈ 9.633