calculate feedback factor in feedback circuit
Each of the gain stages is 4K/(0.026 / 1mA) = 4K/26 = 150X or 42dB. Total low frequency gain is 126dB (2 Million), ignoring any loading by the next stage's DC rin (probably significant, but no beta is given, so ignore that gain-shunting).

Gain will be Rf/Rin = 8x (14dB). There is a rather effective Virtual Gnd activity, thus Rin sets the input resistance.

DC Rout will be 26 ohms/gain_margin = 26 / (2million/8) = 26/ 250,000 or 0.1 milliohm.