What is the relationship between energy (E), momentum (p), mass (m), and the speed of light (c) as described by the equation e2p2c2m2c4?

The equation e2 p2c2 m2c4 describes the relationship between energy (E), momentum (p), mass (m), and the speed of light (c) in the context of special relativity. It shows that the total energy squared (E2) is equal to the square of the momentum (p2) times the square of the speed of light (c2), plus the square of the mass (m2) times the fourth power of the speed of light (c4). This equation illustrates the interplay between energy, momentum, mass, and the speed of light in relativistic physics.