What does the author indicate about the importance of the number 451 in the first part?

In the first part of the novel, we learn that the number 451 is the symbol on the helmet of the firemen, it is a symbol of importance, and it is ironically the temperature at which paper burns.

With his symbolic helmet numbered 451 on his stolid head, and his eyes all orange flame with the thought of what came next, he flicked the igniter and the house jumped up in a gorging fire that burned the evening sky red and yellow and black.

"Well, doesn't this mean anything to you?" He tapped the numerals 451 stitched on his char-coloured sleeve.