I (Erik) stated
It would be a whole lot easier to answer if you took the time to mention the manufacturer.
Any manufacturer can use any convention for their chip numbers..
Horace Ho "replied"
"C" stands for CMOS..
But I don't think "F" stands for "Flash memory" (I am not sure)
It is because there is Flash ROM is 89C52..
And Michael Karas realizing the futility of replying to people that babble instead of answering questions observed:
WHy don't you all just get the DATA SHEETS for the parts that you want to compare and read about how the parts are different or the same. All this banter like "it must be one time programmable" or "and F...I don't know" or "But I don't think "F"" or "(I am not sure)" is a total waste of time.

Why, oh why do you guys bother guessing when the poster does not answer simple questions

In many past instances, there has been "answers" that turned out to be dramatically wrong because the reply came out before the poster of the question responded to a clarification request.

Erik