How to align numbers in all rows

Question

I have a table which contains numbers and their percentages. Because the numbers and percentages length is different, they become unaligned. The following figure illustrates:

As shown in the table, I want the numbers to be aligned. Note that this table is much smaller just to show the problem than the actual table.

The script is:

\documentclass[10pt]{llncs}
\usepackage{graphicx}
\usepackage{sistyle} 
\SIthousandsep{,} 
\usepackage{booktabs} 
\usepackage{array, makecell} 
\usepackage{adjustbox} 

\begin{document}
\title{Test}
\maketitle

\begin{table*}[!tp]
    \centering
    \caption{Summary}
    \label{tab:inspection}
    \begin{adjustbox}{max width=\textwidth}
        \begin{tabular}{lrrr}
            \toprule
            & \multicolumn{3}{c}{\thead{Row}} \\
            \cline{2-4}
            & \texttt{Col \#1} & \texttt{Col \#2}   & \texttt{Col \#3} \\
            \midrule
            Feature \#1             
            & \num{55555}              & \num{222222}           & \num{1111111} \\
            \midrule 
            \quad Feature \#2       
            & \num{44444} (22.11\%)    & \num{222222} (11.11\%) & \num{1111111} (44.44\%) \\
            \midrule            
            \quad \quad Feature \#3     
            & \num{44444} (55.55\%)    & \num{222222} (33.33\%) & \num{1111111} (22.22\%)\\
            \quad \quad \quad Feature \#4      
            & \num{33333} (55.55\%)    & \num{66666} (22.22\%)  & \num{1111111} (100\%) \\
            \bottomrule
        \end{tabular}
    \end{adjustbox}
    \vspace{-10pt}
\end{table*}


\end{document} 

Answer 1

Here is an example using the siunitx package. I have split up the numbers and the corresponding percent values into two columns. (Since I did not have the documentclass you used, I replaced it with article).

\documentclass[10pt]{article}
\usepackage{geometry}

\usepackage{siunitx} 
\sisetup{group-separator = {,}}
\usepackage{booktabs} 


\begin{document}

\begin{table*}[!tp]
    \centering
    \caption{Summary}
    \label{tab:inspection}
        \begin{tabular}{l
                        S[table-format=5]
                        r
                        S[table-format=6]
                        r
                        S[table-format=7]
                        r}
            \toprule
            & \multicolumn{6}{c}{Row} \\
            \cmidrule{2-7}
            & \multicolumn{2}{c}{\texttt{Col \#1}} & \multicolumn{2}{c}{\texttt{Col \#2}}   & \multicolumn{2}{c}{\texttt{Col \#3}} \\
            \midrule
            Feature \#1             
            & 55555&              & 222222  &         & 1111111 \\
            \midrule 
            \quad Feature \#2       
            & 44444& (22.11\%)    & 222222 &(11.11\%) &1111111& (44.44\%) \\
            \midrule            
            \quad \quad Feature \#3     
            & 44444 &(55.55\%)    & 222222 &(33.33\%) & 1111111& (22.22\%)\\
            \quad \quad \quad Feature \#4      
            & 33333& (55.55\%)    & 66666& (22.22\%)  & 1111111 &(100\%) \\
            \bottomrule
        \end{tabular}
\end{table*}


\end{document}