When you deal with noise you have to understand over what bandwidth the noise is spread. If the frequency spectrum of the noise is flat over a given frequency spread it can be expressed as a fixed volts/per root hertz. You will see this spec for many op amps. (nV/root hertz).
Total equivalent AC rms noise voltage will be V noise (in V per root hz) * square root of bandwidth.
Total noise power in a given termination resistance would be (V per root hz * square root of bandwidth) ^2 / R termination.
Noise figure is 10 * log (1 +( total noise power / KTB)) where K = 1.38E-23 , T = operation temp, B = bandwidth.