def convert_to_string(num):
    """
    Converts a base 27 number back into a string

    @param num                  The number we wish to convert
    @return converted_string    The string of that number
    @complexity                 O(M) where M the length of the string
    """
    converted_string = ""
    while num > 0:                                      # Loop for converting back from number to string, backward:
        converted_string += (chr(97 + (num - 1) % 26))
        num -= 1
        num //= 26
    converted_string = converted_string[::-1]           # Flip the order for return purposes
    return converted_string