Wolfram Alpha says average word length in English is 5.1 chars.

450000 words * 5.1 bytes ≈ 2.2 MiB

I like to read novels on my phone in plaintext format. 2001 by Clarke is 368 kiB. Red Mars by Kim Stanley Robinson is 1.1 MiB.

1984 would be 423 kiB, which I consider pretty normal, not "large". But that's subjective, I guess.