Not exactly, you can't do that kind of calculation. Solar panels work only in full sunlight, and only during the day. When there's cloud coverage, the electricity production goes down drastically. I was giving Topaz solar farm in California as a reference, because it's a solar plant of the same magnitude, in about the same sunlight conditions as India. There's about 3 years of track record for Topaz, and so far its best year (2015), it generated 1.3 TWh/year. We're far from the 5.67 TWh/year that you mention. The best upper limit (theoretical) in a solar farm is about 7 hours of sunlight/day, but that's just the theory. In practice it's always lower.
648 megawatts is peak capacity. A fixed-tilt solar PV farm in a good location, like Topaz Solar Farm (and presumably this one) can output 27% of peak capacity averaged over a whole year: https://en.wikipedia.org/wiki/Topaz_Solar_Farm
a 648MW solar power plant produces 5.67 TWh/year (648 365 * 24).*
Is it reasonable to assume that a solar power plant will operate at peak capacity 24 hours per day? (hint: what happens to its output during night hours?)
Nothing happens at night, there's no electricity output. You need some kind of storage on the back-end if you want to store the day's surplus electricity. Molten salt or hydro work well and can store the electricity, in order to distribute it at night time.
But in practice, this is mitigated by the actual power grid, another plant(s) somewhere else would take over at night. On a coal plant it is harder to adjust the load factor on the fly, it is not instantaneous. On a gas plant or a hydro dam, it is a matter of minutes, the turbines can start very quickly. That's why usually when such utility-scale renewable plants are installed, they need to be paired with another load-following plant, such as gas. Nevertheless, a renewable+gas/coal plant means less CO2 emissions, so I guess it's a good thing.