multiprocessing_factorial.py

import operator
from functools import reduce
from multiprocessing import Pool


def product(rng):
        return reduce(operator.mul, rng)

def factorial(number, processes_number):
    result = 1

    with Pool(processes_number) as pool:
        for part in pool.map(product, (range(x, x + number // processes_number) for x in range(1, number - number // processes_number + 2, number // processes_number))):
            result *= part
    
    return result

if __name__ == '__main__':
    number = int(input('Enter a number: '))
    processes_number = int(input('Enter a processes number: '))
    
    print(factorial(number, processes_number))