How many letters does the top answer for “director of the 40-year-old virgin” have?

The most common answer is apatow (6 letters).

Crossword clue: director of the 40-year-old virgin

2 answers found in Letterora's clue database (Wikidata facts, Open Trivia DB, WordNet and Webster definitions — all licensed sources).

apatow 6 letters wd-fact-v3

banks 5 letters wd-fact-v3

English botanist who accompanied Captain Cook on his first voyage to the Pacific Ocean (1743-1820)