https://prepswift.gregmat.com/quizzes/quiz/prepswift-is-it-prime (Question 3)
what is the easy trick to solve this?
Firstly check the “eligibile” primes here. After squaring we find out that 29^2 = 841, Thus making it the closest. Now you just simply check the divisibility of all the prime numbers from 1 - 29. Upon dividing, we get 851/23 = 27, thus making 27 and 23 factors of 851. Hence it’s not a prime. Hope this helps !