Is this property of the number two--that it is the only number (of which I can think) that is has the same answer when it is added or multiplied with itself--termed?

I don't know, Cur.

But Wiki have articles on numbers, including this on the The Number Two.

Good place to start.

Unique

Zero also has that property.

Can you multiply zero?

I mean, you can pick twelve apples and not get any more from a tree and it'll be a logical formula (12 + 0) but can have a logical statement of multiplication with naught?

"Can you multiply zero?"

I feel a slight tug on that connected series of metal links attached to the part of my body between my head and my shoulders.

If you have a business and sell 0 products for 0 days, perhaps...