The Ramanujan constant is an extremely close almost-integer, equal to \(e^{\pi\sqrt{163}} \approx 262537412640768743.9999999999992500725971981\). It came from an April fool's prank by Martin Gardner, where he claimed that \(e^{\pi\sqrt{163}}\) was actually an integer and that Ramanujan himself hypothesized this. Ramanujan had no actual involvement with the number. The number is not at all a coincidence; \(-163\) is a Heegner number and \(e^\pi\) has important properties on the complex plane.