CONVERT_TO_FOREIGN_CURRENCY
Desc. Convert local currency to foreign currency.

CONVERT_TO_LOCAL_CURRENCY
Desc. Convert from foreign currency to local currency

CURRENCY_AMOUNT_SAP_TO_IDOC
Desc. Convert currency to IDOC format

HRCM_AMOUNT_TO_STRING_CONVERT
Desc. Convert amount to string

HRCM_STRING_TO_AMOUNT_CONVERT
Desc. Convert amount from string

CLOI_PUT_SIGN_IN_FRONT  Good one!
Desc. Move the negative sign from the left hand side of a number, to the right hand side of the number. Note that The result will be left justified (like all character fields), not right justifed as numbers normally are.

SPELL_AMOUNT  Ever used one!
Desc. Convert numbers and figures in words

HR_IN_CHG_INR_WRDS  Good one!
Desc. Convert numbers and figures in words