Let 𝑝 be a positive integer and 
𝑞 = 𝑆(𝑝) be the digit sum of 𝑝 such that 
𝑞 + 1 ≡ 0 (mod 2). 
Is it that if 𝑝 is prime then 𝑞 is also prime?


e.g. 𝑝=47(prime)-> 𝑞=4+7=11 (prime)