What is the highest number ever discovered?

Answer 1

There is no highest number or a smallest/lowest number.

Whatever number you have, just add 1 and you get the next bigger number.

Similarly subtract 1 to get the next smallest number.

Numbers are infinite.

The biggest named number is Googolplex.

That's 1 followed by one googol zeroes (a googol - is 1 followed by 100 zeroes = 10^100)

Googolplex = (10)^(10^100)