Otherwise, it depends to some extent on what you're using it for.
"sixty-eight thirty-six" is always wrong (as far as I've heard). It would have to be "six eight three six" for an address, for example, if you don't want to use the full form.
"One seventy-five" would be acceptable for most things.
For dates, you can say, "Thirteen sixty-four" for 1364. I guess you could use "sixty-eight thirty-six" for the date 6836, if needed.
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