(1) 5.6 × 10¹³

[Considering the number of significant digits in the question, strictly our answer should be: 6 × 10¹³]

(2) 2.2 × 10⁸

[Strictly: 2 × 10⁸]

(3) 2.013 × 10^-16

(4) 4.8730 × 10¹⁷