AM radio interference with class A amplifier
I think you are picking up AM radio interference because of the relatively high resistances you are using. High resistances make it easier for a low energy signal like a radio wave to imnpress a voltage on a circuit.  I would suggest 2 remedies. One is to reduce all of your resistors by a factor of 10.  Why do you need to put such a large resistor (R4) in series with your output?  Another remedy is to put a small bypass capacitor across R2 to filter out the AM signal.  If you reduce R2 to 10k, then a capacitor of about 200 pf should be sufficient.  If you reduce R2 to 10k, then use a capacitor of about 2000 pf.