What is the smallest prime divisor of 5^23 + 2^23?
Lets try a list of primes
2: 5^23 is odd 2^23 is even No
3: 5^23 is -1mod3 2^23 is -1mod3 No
5.: 5^23 is divisible by 5 2^23 is not No
7: 5 and 2 are additive inverses mod 7. Exponent is odd. Yessssss
:D