Last updated: before December, 1998
There isn't such a function built into any version of Approach. For Approach v96 there is a LotusScript called ConvertNumberToText in the Archive of Scripts (see section 3. Notices: How to get the Archive of Scripts) which works for numbers up to 999 999 999.
If you are using v2.1 or 3.0* you need create another database with the numbers and related text versions of the numbers, and join it into your current database to the field that you want to appear as text.
It might look something like this:
number text
1 one
2 two
.. ...
27 twenty seven