See for example: https://nl.wikipedia.org/wiki/Categorie:21e_eeuw
In the sort key headings, instead of a '2' it shows '𒑖' (U+12456 CUNEIFORM NUMERIC SIGN NIGIDAMIN) and instead of a '3' it shows '𒑗' (U+12457 CUNEIFORM NUMERIC SIGN NIGIDAESH). The other numbers and letters appear as normal.