Is - 2 considered a real number

Yes. If we wanted to get even more specific, - 2 is an integer, which falls under the label of the real numbers. √-2, on the other hand, is an imaginary number. The square root of - 1 doesn't exist in the real numbers, so we invent a new number i with the property that i² = - 1. Blending real and imaginary numbers together creates complex numbers, numbers with a real and imaginary part. This extension of the number system is tremendously useful because it essentially makes numbers two-dimensional, allowing us to manipulate and study them through a geometric lens.