Incidentally, many other i-adjective stems also have the same function as an interjection, often with a small tsu (っ) at the end of it.
e.g.
熱(っ) (for instance, when touching a hot object)
寒(っ) (cold/chilly)
高(っ) (expensive or hight)
安(っ) (cheap)
怖(っ) (fear)
おいし(っ) (good taste)
まず(っ) (bad taste)
臭(っ) (bad smell)
まぶし(っ) (the glare)
小さ(っ) (too small object)
でか(っ) (too big/large object; 大き from 大きい is not used. Instead, this is from a colloquial equivalent でかい.)
少な(っ) (unexpectedly few things; The counterpart 多 is not used, either. I would use a general word すごっ or like that for unexpectedly many things.)