Find the sum of divisors of 544 which are perfect squares.  Choices:	A) 32	B) 64	C) 42	D) 21	E) None of these
544= 25 + 171 =(2)0+(2)1+(2)2+(2)3+(2)4+(2)5 x (17)0 + (17)1.   Here 20=1 =11 A perfect Square,   22 and 24=16=44 are perfect Squares, Hence,   1 + 4 + 16= 
<gadget id="calculator">1 + 4 + 16</gadget>
<output>21</output>
21. Correct answer is : 21
<result>D</result>
Find the sum of divisors of 544 which are perfect squares.