FINALLY IT WORKS !!!!!

I decided to go for BigInteger library. Tho, still it's bit tricky, since if i want huge number i need to use several variables then * them and get my end result variable. I tested it many many times even with functions etc.. works flawlessly. I even multiplied earth mass in grams, with sun mass in grams, lol. Works nicely. I just wanted to thank everyone helping. Thanks!