I would estimate 1, followed by 21 zeroes. [27 was TYPO! Sorry!] 1,000,000,000,000,000,000,000,000,000 Also known as 10 to the twenty-first power Give or take....

One billion has 9 zeroes. One trillion has 12 zeroes as it corresponds to 1000 billions (12 = 3+9) Therefore, by the algebraic laws of power multiplications, we have: (one billion) times (one trillion) = 1 followed by 9+12 zeroes, i.e. 1 000 000 000 000 000 000 000 (21 trailing zeroes) Are you talking about atoms, molecules, or money in your pockets ?

It is not big .. but it is VERY MUCH! :D ...

omg, things become even more complicated... :-D

Actually, there are two numbering systems used in the world. Short scale (the answers below are short scale), and long scale, in which a billion has 12 zeros and a trillion has 18 zeros. So for a long scale country, a billion trillion has 30 zeros. http://en.wikipedia.org/wiki/Long_scale