def is_strong(n):
d = digit_sum(n)
if is_prime(n/d):
return True
return False
from Useful import digit_sum
from decimal import*
total = 0
iroot = [x for x in range(1,101) if x not in [1,4,9,16,25,36,49,64,81,100]]
for i in iroot:
getcontext().prec = 102
a = str(int((Decimal(i)**Decimal(.5))*Decimal(10**99)))[0:]
total += digit_sum(int(a))
print total
def is_niven(n):
d = digit_sum(n)
if not n % d:
return True
return False
