How can the decimal value of the sha256 hash be lower than one?

Question

In bitcoin mining the sha256(sha256(blockheader)) hash has to be lower than 1/difficulty, right?. But how can a hex value be lower then 1. For example the hash of the genesis block is 000000000019d6689c085ae165831e934ff763ae46a2a6c172b3f1b60a8ce26f which is in decimal 10628944869218562084050143519444549580389464591454674019345556079 which is not lower than 1/1 which was the difficulty in the genesis block.