QUESTION:
What is the land area of Mars in millions?

ANSWER:  
Since there is no liquid on the surface of Mars, all of the surface of
Mars is land area.  As the diameter of Mars is approximately 6,790
kilometers, the surface area is 144.84 million square kilometers (pi*D^2). 
As a side note, although Mars is little more than 1/2 the diameter of
Earth, since about 2/3 of the Earth is covered with water, Mars 
has almost 83% of the Earth's land area.