23. 0.5\sqrt[0,1]{1^{-1}}

$$0.5 \sqrt[0.1]{0.1^{-1}} = \frac{1}{2} \cdot (\frac{1}{10})^{-10} = \frac{1}{2} \cdot (10^{-1})^{-10} = \frac{1}{2} \cdot 10^{10} = \frac{10^{10}}{2}$$