Let 𝑝 be a positive integer (𝑝 < 997) 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)
Digit sum of a prime number
Kelvin
- 15
- 2