The number 200,000,000,000,000,000,000 is 2 x 1020 (i.e., 2 times 10 raised to the power of 20), or 200 quintillionin the decimal system, or 200 exaeons (200E in mathematical shorthand) in the metric system. Refer to the Math.com link, below, for more information.
100000000000000000000 + 100000000000000000000 = 200000000000000000000
Two hundred quintillion.
200,000,000,000,000,000,000 200 billion billion or 200 million trillion
2*1020 this is called 200quintillion a quintillion is a number with 18 zeros a sextillion is a number with 21 zeros your number has 20 zeros therefore it is not quite a sextillion yet.