The Star Spangled Banner spans 1.5 octaves.
That’s more range than most singers can reach comfortably.
The trickiest part is that it starts about two notes from its bottom. Most songs start around the middle of their range. If you try that with the Star Spangled Banner you’ll hurt yourself when you try to get up to the “rockets red glare”.
I can sing it comfortably. But not exactly professionally, though our high school chorus won best in state. If I sang all day and took lessons, I’d be passably good. My cat would probably bite me though.