Indonesian number converter, eg 123 -> seratus dua puluh tiga. Works up to 10^100 - 1. Created out of boredeom. Maybe I should port it to JS.

number_to_indonesian.py

ZERO = 'nol'
ONE_SHORTHAND = 'se'
TEN = 'puluh'
TEEN = 'belas'
HUNDRED = 'ratus'
DIGIT_TO_WORD = {
    '1' : 'satu',
    '2' : 'dua',
    '3' : 'tiga',
    '4' : 'empat',
    '5' : 'lima',
    '6' : 'enam',
    '7' : 'tujuh',
    '8' : 'delapan',
    '9' : 'sembilan',
}

GROUP_NAMES = ['ribu', 'juta', 'miliar', 'triliun',
    # sorry folks, google translate only goes up to 10^12 so had to make my own up
    'kuadriliun', 'kuintiliun',
    'sextiliun', 'septiliun', 'oktiliun', 'noniliun', 'desiliun', 'undesiliun', 'duodesiliun', 'tredesiliun', 'kuatordesiliun', 'kuindesiliun',
    'sexdesiliun', 'septendesiliun', 'oktodesiliun', 'novemdesiliun', 'vingtiliun',
    'unvingtiliun', 'duovingtiliun', 'trevingtiliun', 'kuatorvingtiliun', 'kuinvingtiliun',
    'sexvingtiliun', 'septenvingtiliun', 'oktovingtiliun', 'novemvingtiliun', 'trigintiliun',
    'unatrigintiliun', 'duotrigintiliun']

def number_to_words(number: int) -> str:
    if number == 0:
        return ZERO

    number_str = str(number)[::-1]
    chunks = list(create_chunks(number_str, 3))

    result = ''
    for idx, group in enumerate(chunks):
        group = group[::-1]
        if group == '000':
            continue

        group_idx = idx - 1
        if len(GROUP_NAMES) - 1 < group_idx:
            raise Exception(f'Error: ran out of group names (highest is \'{GROUP_NAMES[-1]}\', equal to 10^{3 * (group_idx)})')
        
        group_result = group_to_words(group)

        if group_idx >= 0:
            if group_result == DIGIT_TO_WORD['1']:
                group_result = ONE_SHORTHAND + GROUP_NAMES[group_idx]
            else:
                group_result = group_result + ' ' + GROUP_NAMES[group_idx]
        result = group_result + ' ' + result
            
    result = result.strip()
    return result

def group_to_words(group: str):
    ''' Like set multiplier but for a whole group '''

    result = ''

    if len(group) >= 3 and group[-3] != '0':
        result += set_multiplier(group[-3], HUNDRED) + ' '
    if len(group) >= 2 and group[-2] != '0':
        is_teen = group[-2] == '1' and group[-1] != '0'
        if is_teen:
            result += set_multiplier(group[-1], TEEN) + ' '
        else:
            result += set_multiplier(group[-2], TEN) + ' '
    if len(group) >= 1 and group[-1] != '0' and (len(group) == 1 or group[-2] != '1'):
            result += DIGIT_TO_WORD[group[-1]] + ' '

    result = result.strip()
    return result

def set_multiplier(digit: str, suffix: str) -> str:
    ''' Turns (2, puluh) into (dua puluh) '''
    if digit == '1':
        return ONE_SHORTHAND + suffix
    else:
        return DIGIT_TO_WORD[digit] + ' ' + suffix

def create_chunks(data, n: int):
    n = max(1, n)
    return (data[i:i+n] for i in range(0, len(data), n))
  
if __name__ == '__main__':
    user_input = int(input('Enter a number to convert: '))
    print(number_to_words(user_input))