Well, my old typewriter does have a # key. It is shift-3 just where it is on my computer keyboard.

Top row keys:
"#$%_&'()* over the digits 2-0 and -.

To the right of the P we have ½ and shift to get ¼.

To the right of the L we have ¢ and shift to get @.

To the right of the M we have , . (both shift and non -shift) and / and shift for ?.

Quickie quiz: What key is missing and how did we get the character back in those good old days? And, no, I don't mean the numeral 1.