Thanks for the shoutout. The package on hex is ex_cldr_numbers (I am the author). Some examples from the readme:

Formatting numbers as words, ordinals and roman numerals

• As words. For example, formatting 123 into “one hundred and twenty-three” for the “en” locale. The applicable format types are :spellout and :spellout_verbose.

iex> MyApp.Cldr.Number.to_string 123, format: :spellout
{:ok, "one hundred twenty-three"}

iex> MyApp.Cldr.Number.to_string 123, format: :spellout, locale: "de"
{:ok, "ein­hundert­drei­und­zwanzig"}

iex> MyApp.Cldr.Number.to_string 123, format: :spellout, locale: "fr"
{:ok, "cent vingt-trois"}

iex> MyApp.Cldr.Number.to_string 123, format: :spellout, locale: "th"
{:ok, "หนึ่ง​ร้อย​ยี่​สิบ​สาม"}

iex> MyApp.Cldr.Number.to_string 123, format: :spellout, locale: "he"
{:ok, "מאה עשרים ושלוש"}

iex> MyApp.Cldr.Number.to_string 123, format: :spellout, locale: "es"
{:ok, "ciento veintitrés"}

iex> MyApp.Cldr.Number.to_string 123, format: :spellout, locale: "zh"
{:ok, "一百二十三"}

iex> MyApp.Cldr.Number.to_string 123, format: :spellout_verbose
{:ok, "one hundred and twenty-three"}

• As a year. In many languages the written form of a year is different to that used for an arbitrary number. For example, formatting 1989 would result in “nineteen eighty-nine”. The applicable format type is :spellout_year.

iex> MyApp.Cldr.Number.to_string 2017, format: :spellout_year
{:ok, "twenty seventeen"}

• As an ordinal. For example, formatting 123 into “123rd”. The applicable format types are :ordinal, :spellout_ordinal and :spellout_ordinal_verbose.

iex> MyApp.Cldr.Number.to_string 123, format: :ordinal
{:ok, "123rd"}

iex> MyApp.Cldr.Number.to_string 123, format: :spellout_ordinal
{:ok, "one hundred twenty-third"}

iex> MyApp.Cldr.Number.to_string 123, format: :spellout_ordinal_verbose
{:ok, "one hundred and twenty-third"}

iex> MyApp.Cldr.Number.to_string 123, format: :ordinal, locale: "fr"
{:ok, "123e"}

iex> MyApp.Cldr.Number.to_string 123, format: :ordinal, locale: "zh"
{:ok, "第123"}

• As Roman numerals. For example, formatting 123 into “CXXIII”. The applicable formats are :roman or :roman_lower. Note that roman number formatting is only supported for numbers between 1 and 5,000.

iex> MyApp.Cldr.Number.to_string 123, format: :roman
{:ok, "CXXIII"}

iex> MyApp.Cldr.Number.to_string 123, format: :roman_lower
{:ok, "cxxiii"}

iex> MyApp.Cldr.Number.to_string 12345, format: :roman_lower
{:ok, "12,345"}