Here is an example:
\documentclass{scrartcl}
\usepackage[quotient-mode = fraction]{siunitx}
\begin{document}
\[\SI{1 / 2500 \pi ^ 2}{\micro \farad}\]
\end{document}
It produces:
siunitx
error: "invalid-token-in-number"
Thank you for your help in advance!
Best Answer
The number parser can be disabled using
for this single case or generally with
As to the 'why' part: the package is focussed on physical quantities, and real measurements cannot delivery
\pi^2
or similar as an outcome, only (here)or similar