What is the greatest prime factor of 4^6 - 1?	Choices:
A) 13
B) 17
C) 19
D) 23
E) 29
4^6-1 = (4^3-1)(4^3+1) = 63*65 = 7*9*5*13   The answer is 13.
<result>A</result>
What is the greatest prime factor of 4^6 - 1?