Add digits is prime or not

Problem to sum the digits and continue the same process until length become one. If final value is prime number print "YES". Otherwise print "NO".

Example-1:

Input    : num = 123456
Output   : YES
Explain  : 1+2+3+4+5+6 = 21
           2 + 1 = 3.(It's prime number).

Example-2:

Input    : num = 12345
Output   : NO
Explain  : 1+2+3+4+5 = 15
           1 + 5 = 6.(It's not a prime number).

Solution

num = 123456

if(num % 9 == 0 and num != 0):

    k = 9

else:

    k = num % 9

for i in range(2,k):

    if(k % i == 0):

        print("No")

        break

else:

    print("Yes")

Output

Yes