there are 21 zeros
There are 21 zeros in a sextillion. in other words, it is a 1 followed by 21 zeros. example: 1,000,000,000,000,000,000,000.
There is no specific name for a number followed by 23 zeros, seven and eight zeros would be ten million and hundred million respectively (6 is a million and 9 is a billion). The name for a number followed by 21 zeros is sextillion and the name for a number followed by 24 zeros is a septillion. So, for example, 7 followed by 23 zeros would be equivalent to 700 followed by 21 zeros and so would be called Seven hundred sextillion.
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.
It has 21 zeros, because 'Giga' means 'a Billion'. Thus, one GigaTrillion is 1 Billion-Trillion. A billion has 9 zeros, and a trillion has 12 zeros. However, if you are referring to the United Kingdom, a billion has 12 zeros and a trillion has 18 zeros, so it would be 30 zeros.
there is 21 zeros in 6 sextillion it looks like this 6,000,000,000,000,000,000,000