How is the title of Fahrenheit 451 significant?

Opinions differ on where Ray Bradbury came up with the
temperature of 451 degrees Fahrenheit as the definitive temperature at which paper
burns. A scholarly text (cited below) gives the general autoignition temperature of
paper to be 450 degrees Celsius, which would be about 840 degrees Fahrenheit; it is
possible that Bradbury misremembered Fahrenheit for Celsius. Regardless, the temperature
and number are used in the novel to symbolize firemen and their job, which is to burn
things rather than extinguishing them. Fireman helmets, jackets, and kerosene canisters
are all marked with 451, to show their purpose; the repetition of the number serves to
remind firemen of their job, and to show the citizens of the city that they are at the
government's mercy, even to the point of non-court-sanctioned killing in the pursuit of
burning books.