The numbers I have been lead to believe were about 200 preproduction Ki-84s, a bit over 3,000 Ki-84-1a, about 300 Ki-84-1b and less than 10 Ki-84-Ic. Total production was just over 3,500.
I should also note that the Ki-84-1a run used a variety of engines, from the lower power Ha-45-11 to the much more powerful Ha-45-21.