According to wikipedia It has a height of 6,191 meters, a prominence of 6,144 meters, and a "col" of 6,191 - 6,144 = 47 meters. Totally checks out!
I assume the lowest point on the "mountain ridge" connecting the two peaks must be somewhere in the Panama Canal, or at least it cannot be higher than that. From what I found, the highest place in the Panama canal is Gatun Lake.
According to wikipedia, Gatun Lake has a surface elevation of 26m. This is less than the 47 I found for the "col" between Denali and Aconcagua.
So where do the 47m come from?