python3

ginvaelEN_mission008.py

import string

# num = msg * C
# We know num, so we have to check every possible C,
# but there's a hint "P.S.2. It's just two bytes.",
# so we only check two-byte numbers

num = 1087943696176439095600323762148055792209594928798662843208446383247024 # given number

# converts integer to array of its bytes
def to_byte_array(n):
    # Byte order could be big-endian or little-endian,
    # I assumed big, if it's incorrect, we would get string in reverse order
    return n.to_bytes((n.bit_length() + 7) // 8, byteorder='big')

def try_num(n):
    a = to_byte_array(n)
    a = [chr(x) for x in a] # convert array of bytes to array of ascii characters

    if(not all(c in string.printable for c in a)): # check if all characters are printable
        return

    msg = ''.join(a) # convert array of characters to string
    print(msg)

for C in range(1,256**2): # we check only two-byte numbers (except 0)
    if(num % C == 0): # check if num is the multiple of C
        try_num(num // C)