Oracle 11g - Data restriction from VARCHAR2 Column

Dear All,

I am querying customer numbers (data type is Varchar2) from 41000 to 41299 in hz_cust_accounts table using below query

SELECT *
FROM hz_cust_accounts
WHERE account_number >= '41000'
AND account_number <= '41299'

But i am also getting 4140, 4150 customer data.

Please suggest me How to restrict the data between the range of customers from 41000 to 41299.

Regards,

Anjana J