This one line command will list each folders in current path by the number of files inside of it, recursively.
find . -type d -exec sh -c "fc=\$(find '{}' -type f | wc -l); echo \"\$fc\t{}\"" \; | sort -nr
find . -maxdepth 1 -type d -exec sh -c "fc=\$(find '{}' -type f | wc -l); echo \"\$fc\t{}\"" \; | sort -nr
