The numbers i, Π & e are special, with i being special in an awkward way.
Since it can be shown that i² equals both 1 and -1, a contradiction that is swept under the carpet for fear of a reprisel from the universe.
Recall that i is useful notation for shortening the written representation of imaginary numbers, it is defined as √-1.
Since i² = (√-1)² = √-1 × √-1 = √(-1 ×-1) = 1
… i² is (√-1)² and because squaring a root ( i.e (√A)² = A ) effectively cancels the operation out … we end up with -1.
A which point there’s usually a bit of shoulder shrugging and scuffling away.