A Hectad is an area 10 km x 10 km square. The total surface area of Earth is approximately 510.1 million square kilometers.
1 square kilometer is equalized to 100 H51 Tokens. So, 510.1 million square kilometers is: 510.1 million square kilometers * 100 = 51.01 billion H51s. Earths surface of 510.1 million square kilometers is equalized to 51.01 billion H51 Tokens.