Larger the value of n, the larger is the orbit radius
The negative sign in equation simply means that the energy of electron bound to the nucleus is lower than it would be if the electrons were at the infinite distance from the nucleus
Equation can be used to calculate the change in energy when the electron changes orbit
For n=1, the electron has a more negative energy than it does for n=6, which means that the electron is more loosely bound in the smallest allowed orbit
E ∝ -1/n². As n increases, E → 0. The energy of the electron is taken as zero at infinity where it is not under the influence of any external force. As it approaches closer to the nucleus, the electrostatic attraction force decreases its energy. The lesser the energy, the more stable is the electron. As r increases, energy increases and n increases.