Voltage divider can not be of any value, as the fan needs some current, namely 0.06 Amp (or, 60 miliAmps).
Using 10 kOhm resistor would limit current to 1.2 miliAmp.
The fan's coil is the lower part in voltage divider, thus just one resistor (upper part) is needed. Like Larry1 suggested, 200 Ohms.
The substitute resistor for fan's coil is just around 200 Ohm, (12 V divided by 0.06 A).
Small bulbs (from old flashlight, or, from old Christmas tree lights) could be tried, in series or parallel (assuming they are still available...).
Probably lowering the voltage to 8- 9 V would reduce noise enough, so, maybe 100 Ohm resistor or similar would do the trick.
6 silicon rectifying diodes, connected in series, would cause voltage drop about 4 Volts (6 x 0.7 V = 4.2 V).
Cheers, polgyver