siunitx and engineering 'E' notation

Question

Is it possible to use the siunitx package to typeset numbers with the "E" notation so that the output might look like

1E3

instead of

1 x 10^3

Answer 1

Yes, it's possible, see p. 29 in the manual:

\documentclass{article}
\usepackage{siunitx}
\sisetup{output-exponent-marker=\ensuremath{\mathrm{E}}}

\begin{document}
\num{1e3}

\SI{2.3e5}{m}
\end{document}