Gravitational force between 2 objects . . .
F = G · m₁ · m₂ / D²
-- You said that F = 3.5 x 10²² Newtons.
-- G = the gravitational constant = 6.67 x 10⁻¹¹ N m² / kg²
-- You want to find D .
F = G · m₁ · m₂ / D²
Multiply each side by D² . . . D² · F = G · m₁ · m₂
Divide each side by F . . . D² = G · m₁ · m₂ / F
So finally . . . D = √(G · m₁ · m₂ / F )
D = √(6.67 x 10⁻¹¹ N·m²/kg² · Earth mass · Sun mass / 3.5 x 10²² N)
D = 4.37 x 10⁻¹⁷ · √(Earth mass · Sun mass) meters
