User blog comment:Jefleo/2^(2^63)/@comment-30754445-20170516105017

If you're refering to the mainspace of the wiki, then - generally - numbers which can only be represented by a formula (such as 2^2^63) are not allowed there. It's a silly rule in my opinion, but that's how things work here.

OTH, If you just want to make the comparision and/or inviite discussion, you can to it on your blog.

Speaking of which:

As ARsygo said, the number 2^2^63 is a Class-3 number. "Class-3" means that:

1. The number which is difficult or impossible to write in full (what you refered to as "uncomputable")

2. We can figure out the exact number of digits, as well as the leading digits (it has exactly 2776511644261678567 digits which start with 13809...)

4^63 - on the other hand - is a Class-2 number: A number which can be written in full, but cannot be precieved directly as a collection of items (if you had 4^63 dots in your field of vision, you wouldn't see the individual dots).

So that's one kind of comparision we could do between these two.

As for the idea of "remove the decimal point from pi":

The result wouldn't be a number at all. Since there's an infinite number of digits, it would be bigger than any number, so it can't be - itself - a number.

(also would such a number be odd or even? That depends on the "last digit" of pi, but there's no such thing)

And as a side note:

In googology (and math) the word "uncomputable" is a technical term which means something very different then the way you used that word. Basically, an "uncomputable" number is a number which cannot be computed by a computer with unlimited resources.

This idea seems absurd on the face of it. Intuitively, with unlimited time and memory, we should be able to calculate anything, right? Well, as it turns out, our intuition is wrong. There are mathematical problems which cannot be computed even with unlimited resources, which is why this distinction between "computable" and "uncomputable" is an important one.

This fact is one of the most amazing discoveries of modern mathematics, and it is quite relevant to googology as well. It doesn't come to play for numbers as small as 2^2^63, though. Uncomputable expressions usually grow very very very fast (the architypical uncomputable function, known as the "Busy Beaver" function, already surpasses 2^2^63 and even 2^2^2^2^63 for x=7)