ORA-01722: invalid number in 10g

 Hello, I am getting ORA-01722: invalid number error in 10g, not in 9i.

SELECT COUNT(1) FROM dcsw_owner.STATIC_META_INFO
WHERE LABEL_NAME = 'APL_STATUS'  AND STATUS = 'P' 
AND ACCESS_KEY = 140

or

SELECT COUNT(1) FROM dcsw_owner.STATIC_META_INFO
WHERE LABEL_NAME = 'APL_STATUS'  AND STATUS = 'P' 
AND to_number(ACCESS_KEY) = 140

ORA-01722: invalid numbe

SELECT COUNT(1) FROM dcsw_owner.STATIC_META_INFO
WHERE LABEL_NAME = 'APL_STATUS'  AND STATUS = 'P' 
AND ACCESS_KEY = '140'

No Error now.

In 9i  ALL the three statements work fine. Data of this table in both 9i and 10 is same.

Thank You