The product of two consecutive positive integers is 156. Their sum is:

Since $12^2=144$ and $13^2=169$, the two integers must straddle 12.5, and indeed $12\times 13=156$. Their sum is 12 + 13 = 25. (Equivalently $n^2+n-156=0$ factorises as $(n-12)(n+13)=0.$)