How do you say that number in words 4720000000000000000000?

The number 4,720,000,000,000,000,000,000 can be said as "four sextillion seven hundred twenty quintillion." In scientific notation, this number can be written as 4.72 x 10^21. The prefix "sextillion" indicates a number followed by 21 zeros, while "quintillion" indicates a number followed by 18 zeros.