Programming Challenge Numbers to Text?

[Shane Hathaway]

plug.org at 2nerds.com wrote:
> This lisp expression:
> 
>   (format t "~r~%~r~%~r~%~r~%~r~%" 1 15 91283 4918239 2147483647)

What does that really mean, and how would I find out?  What would happen 
if I used only four "~r~%" sequences instead of five?  What about i18n? 
  This looks very obtuse to me, and I would consider it a mark *against* 
lisp.  I'd much rather use a function with a name like "spell_int" than 
a series of symbols.  Is your syntax actually helpful in some way I'm 
not seeing?

Shane