The german phone code 033635 represents Arensdorf (Kreis Oder-Spree) in Brandenburg.
Note for calls from abroad: In addition to the German country code (+49 or 0049) you can omit the foregoing zero of the dialling code for Arensdorf (Kreis Oder-Spree). So you can dial +4933635... and add the number of the phone line you want to reach.