This uses the Dropbox Python SDK to download a file from the Dropbox API at the remote path /Homework/math/Prime_Numbers.txt to the local file Prime_Numbers.txt:
import dropbox
dbx = dropbox.Dropbox("<ACCESS_TOKEN>")
with open("Prime_Numbers.txt", "wb") as f:
metadata, res = dbx.files_download(path="/Homework/math/Prime_Numbers.txt")
f.write(res.content)
<ACCESS_TOKEN> should be replaced with your access token.