Run the command "shuf -i 0-9999999 -r" with one argument at a time, take the first result, and replace {} with the result in the command "echo {} | sed s/[0-9][0-9]*/\1/g".
xargs -n 1 shuf -i 0-9999999 -r | head -n 1 | xargs -I {} echo "echo {} | sed s/[0-9][0-9]*/\1/g"