A-7713 is the serial number assigned to the protagonist Elie by the Nazis after arriving at the concentration camp. Instead of a name, each of those who come to such German camps receives a set of letters and numbers. Nazis track all their prisoners more conveniently this way.
Detailed answer:
In early 1943, Nazis begin tattooing prisoners with a five-digit serial number stamped on their arm. Children receive numbers on their feet since they are small. A number consisting of five digits would not fit on a small hand.
The serial number is tattooed to avoid the possibility of its removal from the body. After the death of the prisoner, Nazis would confiscate and destroy their clothes. A tattoo on the arm is the only way to identify a dead person and establish their identity.
Buchenwald is a men’s camp. The prisoner has to memorize his serial number in German during the first day. From that moment on, a set of numbers replace the name.
To save time, prisoners who get the death penalty immediately upon arrival do not receive numbers. In most concentration camps, the serial numbers of the killed and disposed of prisoners move to new arrivals. Nazis do it to hide the actual number of victims.
A-7713 does not have any specific significance or meaning. It doesn’t reveal any information about the person. This is a number that Nazis used instead of prisoners’ real names.
Ellie’s character comments on the issue like this: “But I still have it on my arm – A7713. At that time, we were numbers. No names, no identity