A common recommendation for printing is 300 ppi, so approximately 17x10 in. (16x9 is probably easier to find)

For a poster or canvas you can often go a little lower, into the 200-250 ppi range without too much difference in quality.

If you dropped all the way down to 160 ppi, then you could do a 32 x 18 in. print.

The best path, however, is to ask your printer what they recommend.