This movie was a blockbuster and completed 329-day run at the box office. Since then, it has achieved cult status and is regarded as a classic by critics and audiences alike.
The number "Kannae Kalaimanae" was written by Kannadasan, and was written in "about two minutes" time. Coincidentally, it was the last song which he wrote, before his death in 1981.
Balu Mahendra gave a lot of space for both Kamal Haasan and Sridevi to improvise a bunch of scenes. The most famous improvised scenes being the scene where Kamal gets angry at Sridevi for the burnt food, the scene where Kamal Haasan imitates a monkey to make Sridevi laugh and the now iconic climax sequence.
When M. Night Shyamalan made his first film 'Praying with Anger' he approached Balu Mahendra to do the cinematography but for some unknown reasons Mahendra declined.