數學最大的數

9^(9^9)=9^387420489=9的387420489次方

即 9×9×9×9×9×9×9.............×9

總共有 387420489個9相乘，將近有4億個9相乘。


2013-02-09 02:33:24 補充：
取 log 9(9^9) = 387420489×(log 9)
= 387420489×0.9542 = 369676630.6

所以這個數有 369676631 位，將近3億7000萬位

2013-02-09 15:28:01 補充：
Tetration uses 2"9"s only,not 3"9"s
....9.....
......9...
3"9"s (or more) is no more called teration，it's called pentation.
In the case of 9"9"s used,It's written as
"9↑↑↑9" or "9↑3 9"

2013-02-09 15:31:06 補充：
Still, only 2"9"s used，not 3"9"s.

In the case of 3"9"s used，It's written as
"9↑↑↑3" or "9↑3 3"
Only one "9" used.
That's why I didn't use teration or pentation or the answers.

2013-02-09 15:31:47 補充：
I'm not sure if repeated tetration can be used or not,
If this is the case，then I agree the number can be bigger.
....9..........
......9........
........9......

2013-02-09 15:33:31 補充：
correction:

That's why I didn't use teration or pentation for the answers.

For example tetration, pentation, ...

應該寫出所能使用之(二元)運算，否則要多大都可以。