The closest multiple

#! /usr/bin/env python3

def multiple(number, factor):
    if number == 0:
        return factor
    if factor == 0:
        return 0
    if number == factor:
        return number
    if number < factor:
        return factor
    if number > factor:
        return (number + factor - 1) // factor * factor

# [multiple(i, j) for i in range(1000) for j in range(1000)]
# 1000004 function calls in 0.965 seconds