The ignition point of paper is around 842 degrees fahrenheit. The remark about 451 being the temperature books burn was used as a selling point for the book. I don't know why Bradbury didn't just call it Fahrenheit 842.
Still, whatever the reason for the title, it is one of my all-time favourite novels. A joy to read...which makes the subject matter of the novel all the more ironic
After I read your post I decided to look it up out of curiostiy and I keep finding site after site claiming it to be 451, with a small vairance depending on the chemicals and such in the paper. So may I ask were you got your information so I can determine which is correct?
Autoignition temperature - Wikipedia, the free encyclopedia