The average eukaryotic cell is about 100 μm (100 x 10-6 m. = 10-4 m.) long.
You have 200 trillion
(2 x 1014) somatic cells (p. 230).
Total length of your cells lined up end-to-end:
(2 x 1014) x (10-4 m.) = 2 x 1010 m. = 2 x 107 km.
The earth's circumference is 40 million m. (40 x 106 m. = 4 x 107 m. = 4 x 104 km.
2 x 107 km. / 4 x 104 km. = 500: your cells can wrap around the earth 500 times.