ProjectEuler#16 Power digit sum

#2**15 = 32768 and the sum of its digits is 3 + 2 + 7 + 6 + 8 = 26.

#What is the sum of the digits of the number 2**1000?

#Analysis
#Calculate 21000, split the digits and add them together.

digits = str(2**1000)
acc = 0
for i in range(len(digits)):
    acc += int(digits[i])

print acc