4767 x 75 x 365 = I get 130,500,000 cm³/person/lifetime. You got 130,000,000,000,000,000.
There are 10¹⁵ cubic centimetres in a cubic kilometre, not 10⁶. I think all your numbers are for m³, not km³, a factor of a billion out, so your final figure should be 39 km³.
I think something went very wrong there!
4767 x 75 x 365 = I get 130,500,000 cm³/person/lifetime. You got 130,000,000,000,000,000.
There are 10¹⁵ cubic centimetres in a cubic kilometre, not 10⁶. I think all your numbers are for m³, not km³, a factor of a billion out, so your final figure should be 39 km³.