I'm going to ASSUME your estimate is approximately reasonable and note that 1.8% of the total land surface area of the earth is 3,544,000 sq. miles.
Now, of course the HUGE thing you FAIL to take into account is the fact that solar PV arrays function not unlike land as well. They also absorb short wavelength radiation and downconvert it and re-radiate it back out as IR. It is obviously less so than say a black roof of a building but probably not much.
The numbers don't even begin to make sense and the reality on the ground overlooks basics of physics.