450 billion people, on only three planets?
Earth could only sustain 20 billion at best without having people starve to death.
Mars is significantly smaller than Earth, with very a thin, poisonous atmosphere. It can sustain 10-14 billion people assuming we terraform it and can take full advantage of the land, the next PLANET we could colonise would be Venus, which has very harsh conditions, for example, acid rain, tornadoes, super storms, making full advantage of the land very difficult. We won't have efficient use of Venus before colonising the next closest large solid rock body. We'd have to colonise all over the solar system just to get close to 200 billion.
I don't think the author even tried to make this a realistic number.

Base +4, rulmo -5, Trollaroth -6, fxd001 -8, overall pretty good -6, ahscreep -3, bwanaman -14, Gojii -6, arcgher -6

Why bother with logic, I'm here for the fap.

Base +6, rulmo +5, Trollaroth +6, overall pretty good +6, Gojii +6, arcgher +6