\documentclass[]{standalone}
\usepackage[]{graphicx}
\usepackage{tikz}
\usepackage{pgfplots}
\pgfplotsset{compat=1.17}
\tikzset{>=latex}
\usetikzlibrary{arrows,arrows.meta}
\usepackage{steinmetz}
\newcommand*{\equal}{=}
\usepackage{tikz-3dplot}
\usetikzlibrary{decorations.markings}
\tikzset{->-/.style={decoration={
markings,
mark=at position #1 with {\arrow{>}}},postaction={decorate}}}
\begin{document}
\begin{tikzpicture}[scale=2]
\draw (0,0) circle [radius=1];
\fill ({cos(pi/2 r)}, {sin(pi/2 r)}) circle [radius=0.1] node[above=5pt] {1};
\fill ({cos(pi/2 r - 1*2*pi/3 r}, {sin(pi/2 r - 1*2*pi/3 r)}) circle [radius=0.1] node[right=5pt] {2};
\fill ({cos(pi/2 r - 2*2*pi/3 r}, {sin(pi/2 r - 2*2*pi/3 r)}) circle [radius=0.1] node[left=5pt] {3};
\end{tikzpicture}
\end{document}