To brute force hack an ATM PIN is 9,999 combinations.
A Bitcoin private key is 115,792,089,237,316,195,423,570,985,008,687,907,853,269,984,665,640,564,039,457,584,007,913,129,639,936 combos.
In case you're curious, that's pronounced: 115.792 quattuorvigintillion. Approximately.