We want to know how many words our story will have.
We know that the book where the story will be print is 570 pages, with a page size of 8.5x11 inches.
From the research, we know that in a 8.5x11 in. page will fit 800 words. So if we have 570 pages, the story will have:

Answer: the story will have approximately 456,000 words.