24 : 29 :: 32 : ? Choose the number that completes the analogy.

Each number is answered by the first prime lying above it. Above 24 the numbers 25, 26, 27 and 28 all break up, and 29 is the first that does not. Above 32 the numbers $33(3\times 11),34,35(5\times 7)$ and 36 all break up, so 37 is the first prime. 33 and 35 are the composite near misses, and 41 is a genuine prime but 37 stands before it.