"Ultimately, there is nothing magical about the human brain."
No! However, they are biological entities, which "recapitulate" millions of years of evolution.
We, indeed, "unconsciously" invented mathematics in the Savannah millions of years ago when 12 Homo hunters came to figure out, driven by their innate animal fairness, that they had to divide the 3 preys they just killed into 4 equal parts while taking the quality of each part in consideration.
There goes Kant's "non-empirical" aspect of mathematics and his notion of "synthetic a prior knowledge."
Comparing AI to human intelligence is the same as comparing hammers to blueprints; they are both needed to build houses but uncomparable!