In bitcoin, private keys range from 1 to
n-1, with
n being the order of the base point G for the secp256k1 curve. In simple terms, the largest valid private key (
n-1) is:
FFFF FFFF FFFF FFFF FFFF FFFF FFFF FFFE BAAE DCE6 AF48 A03B BFD2 5E8C D036 4140
It is possible however to use private keys larger than this number, as all private keys are modulo
n. The key you have given as an example leads to an address which has previously been used back in 2017:
https://blockchair.com/bitcoin/address/1CLrrRUwXswyF2EVAtuXyqdk4qb8DSUHCXNote that it's a terrible idea to create your own private key by manually choosing a 64 digit hexadecimal number.