\documentclass[tikz, border=1cm]{standalone}
\usepackage{tkz-euclide}
\begin{document}
\begin{tikzpicture}
\coordinate (o) at (0,0);
\coordinate (a) at ($(o)+(20:2)$);
\draw (o) -- (a) node [midway, above]{$r$};
\draw (o) circle (2cm);
\filldraw (o) circle (2pt);
\foreach \x in {0,1,2,3,4,5}
{
\filldraw ($(o)+(24*\x:2)$) circle (2pt);
%\draw ($(o)+(24*\x:2)$) node[right]{$\sigma_{\x}$};
}
\draw ($(o)+(24*1:2)$) node[above right]{$re^{i\sigma_1}$};
\draw ($(o)+(24*2:2)$) node[above right]{$re^{i\sigma_2}$};

\end{tikzpicture}  
\end{document}