The area code (phone code) 0551 is assigned to 4 locations in Germany. Mainly you reach landlines in Göttingen (Niedersachsen).
|0551||Gleichen, Kreis Göttingen|
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 Göttingen. So you can dial +49551... and add the number of the phone line you want to reach.