diff --git a/account.py b/account.py
index a3fe3567e3..c2ad07fc1c 100644
--- a/account.py
+++ b/account.py
@@ -4,6 +4,8 @@ from decimal import ROUND_DOWN, ROUND_HALF_EVEN, Decimal
 from itertools import groupby
 from operator import itemgetter
 
+from sql.functions import CharLength
+
 from trytond import backend
 from trytond.i18n import gettext
 from trytond.model import MatchMixin, ModelSQL, ModelView, Workflow, fields
@@ -197,6 +199,11 @@ class LandedCost(Workflow, ModelSQL, ModelView, MatchMixin):
                 [sql_table.state], ['cancelled'],
                 where=sql_table.state == 'cancel'))
 
+    @classmethod
+    def order_number(cls, tables):
+        table, _ = tables[None]
+        return [CharLength(table.number), table.number]
+
     @staticmethod
     def default_company():
         return Transaction().context.get('company')