The Ackermann function is a mathematical function that returns really really large numbers. For example, is an integer with over 19,700 decimal digits.
Graham’s number is a holy-moly massively horrifyingly huge number which makes a googolplex look like diddly squit. Actually, it makes numbers which make numbers which make googolplex look like diddly squit look like ant droppings look vanishingly small. It it unimaginably huge. I do not have words to explain how much massively huger than pretty much any number you can think of it is.
As you can imagine, is quite a large number.
PS— I’ll answer the question soon, I want to type out a proper explanation for that.