\documentclass[a4paper]{article}
\usepackage{ifthen}
\usepackage[LGR,T1]{fontenc}
\usepackage{booktabs}
\usepackage{longtable,ltcaption,array}
\usepackage[textwidth=14cm]{geometry} % to fit the number table
\setlength{\extrarowheight}{2pt}
\usepackage{parskip}

\ifdefined \UnicodeEncodingName
  \usepackage{fontspec}
  % \setmainfont{Linux Libertine O} % no GREEK ACROPHONIC ATTIC numbers
  % \setmainfont{Liberation Serif}  % no GREEK ACROPHONIC ATTIC numbers
  \setmainfont{FreeSerif}
\else
  \usepackage{lmodern}
\fi


\usepackage{textalpha}
\usepackage{athnum}

\begin{document}
\title{Test Attic numerals}
\author{Günter Milde}
\date{2022/12/08}
\maketitle

The Greek font encoding is \greekfontencoding.\footnote{
  Since version 2.0 you can use \emph{athnum} also without
  \emph{babel-greek} and with Unicode fonts (if they support the
  ``Greek acrophonic attic'' number symbols for 50, 500, and 5000).}

\begin{tabular}{rrrrrrrrr}
\toprule
1 & 2 & 3 & 4 & 5 & 6 & 7 & 8 & 9 \\
\athnum{1} & \athnum{2} & \athnum{3} & \athnum{4} &
\athnum{5} & \athnum{6} & \athnum{7} & \athnum{8} & \athnum{9} \\

10 & 20 & 30 & 40 & 50 & 60 & 70 & 80 & 90 \\
\athnum{10} & \athnum{20} & \athnum{30} & \athnum{40} &
\athnum{50} & \athnum{60} & \athnum{70} & \athnum{80} & \athnum{90} \\

100 & 200 & 300 & 400 & 500 & 600 & 700 & 800 & 900 \\
\athnum{100} & \athnum{200} & \athnum{300} & \athnum{400} &
\athnum{500} & \athnum{600} & \athnum{700} & \athnum{800} & \athnum{900} \\

1000 & 2000 & 3000 & 4000 & 5000 & 6000 & 7000 & 8000 & 9000 \\
\athnum{1000}& \athnum{2000}& \athnum{3000}& \athnum{4000}&
\athnum{5000}& \athnum{6000}& \athnum{7000}& \athnum{8000}& \athnum{9000} \\

10000 & 20000 & 30000 & 40000 & 50000 & 60000 & 70000 & 80000 & 90000 \\
\athnum{10000}&\athnum{20000}&\athnum{30000}&\athnum{40000}&
\athnum{50000}&\athnum{60000}&\athnum{70000}&\athnum{80000}&\athnum{90000} \\

\bottomrule
\end{tabular}

Some examples:


678 = \athnum{678}, 2022 = \athnum{2022}

Largest ``canonical'' number: 9999 = \athnum{9999}

Largest allowed number: 249999 = \athnum{249999}

Hexadecimal input works, too: \texttt{"10} = \athnum{"10}

Attic numerals in math mode: $a = \textrm{\athnum{678}}, b = \athnum{2022}$

\end{document}