The sentence that is pure hyperbole is part of the narrator's description of the landlord:
He was worshiping, with all his body and soul, but he looked as if he couldn't stir hand or foot.
The landlord is looking at the £1,000,000 bank-note and experiencing a reaction which is common to most people when they behold an exceptionally large sum of money--or when they meet a man who possesses many millions. Mark Twain does not have to be afraid of misrepresenting the landlord's reaction. The reader understands precisely what the man is feeling and discounts the narrator's description proportionately. The landlord is not literally worshipping the bank-note but is stunned at the beauty and the potential of such a wonderful conception and creation.
Part of the quoted sentence is not hyperbolic--the part that says he looked as if he couldn't stir hand or foot. It is the first half of the sentence that contains the hyperbole. The landlord is the first person (after the narrator) who will see this marvelous bank-note. Mark Twain must have felt that he should describe the first man's reaction as one of extreme awe and wonder, because he couldn't keep describing subsequent reactions of other men to the same bill without getting diminishing effects or even incurring disbelief in the premise. The reader will understand that the other men who see the marvelous bank-note will be experiencing feelings comparable to those of the landlord.
Part of what makes the scene so funny is that the narrator acts as if the bank-note is nothing but petty cash.
I reached the note towards him, and said, carelessly:
"Give me the change, please."
Mark Twain continues with more hyperbole.
Then he was restored to his normal condition, and made a thousand apologies for not being able to break the bill, and I couldn't get him to touch it. He wanted to look at it, and keep on looking at it; he couldn't seem to get enough of it to quench the thirst of his eye, but he shrank from touching it as if it had been something too sacred for poor common clay to handle.
The "change" would have amounted to £999,999 plus approximately seventeen shillings, or in American dollars to $4,999,999. The narrator specifies that he had gone to "the nearest cheap eating house."
Mark Twain's story is the prototype of many such stories that have followed since "The £1,000,000 Bank-Note" was published in 1893. Invariably, a couple of fabulously wealthy men make a bet which involves giving some poor passer-by a huge sum of money to dispose of within a short period of time. In Mark Twain's story the protagonist is given the bank-note as a loan for thirty days.