The "solar constant" is 1,370w/m^2. the radius of the earth is 6371km. how much radiation (in w) does the earth receive? => the answer is 1.76 x 10^17 w, but i'm getting a wrong answer.

my approach:

solar constant = 1,380 w /m^2

r_earth = 6371km^2

radiation = x w

surface area of the radiation? = 4pi * r_^2

1380 = x / {4pi* (6371)^2}.

x = 703888 w # which is so wrong.