Hi,
Have a look an excellent open source project called
Humanizer[
^], which has a function called
ToWords()[
^] that provides that functionality.
Snippet from the readme to demonstrate it's usage:
1.ToWords() => "one"
10.ToWords() => "ten"
11.ToWords() => "eleven"
122.ToWords() => "one hundred and twenty-two"
3501.ToWords() => "three thousand five hundred and one"
... hope it helps.