Which is correct: successful or successfully in my context?
"Number of successful processed clients" or "Number of successfully processed client"

Question

Answer

I would say "Number of successfully processed clients" sounds best.

Answer

Both are correct, but mean different things. The first implies that there are many "processed clients," some of whom are successful. (Because "successful" is an adjective, so it must refer to a noun [clients]).  The second implies that you have "successfully processed" many clients (because successfulLY is an adverb [most words ending in "ly" are adverbs], so it must refer to a verb)