1,157,920,892,373,161,954,235,709,850,086,879,078,532,699,846,656,405,640,394,57

[stwenhao]

If it's supposed to be 2^256

No, it should be n-value of secp256k1. But: OP failed to type it twice, and seems to ignore, that n-value is prime, so we are quite safe. It will take a lot of effort to even come close to any real attacks.