Hello,
With Latex, I did this :

\usepackage[colorlinks=true,pdfstartview=FitV,linkcolor=blue,citecolor=blue,urlcolor=blue]{hyperref}
\rfoot{\scriptsize{\textsf{Page~\thepage{}~sur~\pageref{LastPage}}}}


With Context, I tried this unsuccessfully ;

\setupinteraction
    [state=start,
     style=,
     color=\darkred,
     contrastcolor=]

 \setuppagenumbering
        [alternative=,
         location={footer,right},
         command={Page\,\pagenumber\,sur\,\lastpage } ]


Thank you

Fabrice