The number e is more fundamental than π — we just don't teach it that way.

Pi gets the holiday and the tattoos. But Euler's number e ≈ 2.718 shows up in compound interest, population growth, radioactive decay, probability, and the deepest identity in mathematics: e^(iπ) + 1 = 0. Pi describes circles. e describes change itself. If math has a heartbeat, it's e