... 40 in S/4 HANA, and if it contains only numbers (for example 123), then the internal value is stored with leading zeros, for example 000000000000000123 in ECC system. As you can imagine reading 123 ...
This field allows manipulation of visibility of leading zeros. One of the most common example is the material number (MATNR), when there is no letter inside the name of material, it is stored in database ...