cursed.py

from typing import Tuple, List
t = "teen"
y = "ty"
NUMBERS = ["zero", "one", "two", "three", "four",
           "five", "six", "seven", "eight", "nine",
           "ten", "eleven", "twelve", "thir" + t,
           "four" + t, "fif" + t, "six" + t, "seven" + t,
           "eigh" + t, "nine" + t, "twenty"]
TENS = ["thir" + y, "four" + y, "fif" + y, "six" +
        y, "seven" + y, "eight" + y, "nine" + y]

WORDS = {
    10 ** 6: "milion",
    10 ** 3: "thousand",
    10 ** 2: "hundred",
}
WORDS.update(((i + 3) * 10, x) for i, x in enumerate(TENS))
WORDS.update(enumerate(NUMBERS))

CARDINALITIES = list(WORDS.keys())
CARDINALITIES.sort(reverse=True)

IntPair = Tuple[int, int]


def format(n: int) -> List[IntPair]:
    if n == 1:
        return [(1, 1)]
    rem = n
    while rem > 0:
        for i, c in enumerate(CARDINALITIES):
            if rem >= c:
                x, rem = divmod(rem, c)
                yield (x, c)
                break


def nested_format(x: int) -> List[Tuple[List[IntPair], int]]:
    for item in format(x):
        if isinstance(item, int):
            yield item
        else:
            y, c = item
            for (z, cz) in format(y):
                yield from nested_format(z)
                yield cz
            yield c


def n_to_s(n: int) -> str:
    if n == 0:
        return "zero"
    if n == 1:
        return "one"
    toks = list(WORDS[x] for x in nested_format(n))
    if len(toks) == 1 and n > 99:
        toks.insert(0, "one")
    return "_".join(toks)


for x in range(1, 10 ** 6 + 1):
    print(n_to_s(x).upper() + " = " + str(x))

Type annotations are all goofed but I CBA