The largest digits number with only 2 digits alike is 99
If the digits are only used once, each, the largest possible number would be 97,531
This number is 9 999.Or maybe 9999 .
I suspect that it is 6^940 which is 731 digits long. The largest through reordering the digits is only 9640.
You go for 99.
99Another Answer:-99 = 387420489
99 is the largest two digit number. If I can use the digits anyway I want, then 9 to the 9th power is larger
As of January 2016 , the largest known prime number is 2^74,207,281 − 1, a number with 22,338,618 decimal digits.
974. If you mean the largest one with ONLY the digits 4 and 7, then 774. If it can only contain 7 and 4 but doesn't have to have both, then 777.