Some Holocaust deniers use the fact that concentration camp tattoos only go to 6 digits as proof that 6 million Jews couldn't have died in the Holocaust.
Tattooed numbers were used only in one German Nazi camp: Auschwitz. These tattoos were assigned exclusively to prisoners who were registered in the camp. Out of approximately 1.3 million people deported to Auschwitz, only about 400,000 were registered as prisoners and given numbers.
The vast majority of Jews murdered in Auschwitz, around one million people, were never registered; they were murdered in gas chambers right upon arrival and received no tattooed number.
Moreover, tattoos were not exclusive to Jewish prisoners. Others, including Poles, Roma, Soviet POWs, and others, were also registered and tattooed at Auschwitz. Other concentration camps had entirely different systems for identifying prisoners and did not use tattoos at all.
To suggest that every Jewish victim of the Holocaust received a tattooed number, and to use the limited length of those numbers to cast doubt on the scale of the genocide, is not only factually false. This kind of distortion is a deliberate tactic used by Holocaust deniers to insult the memory of victims.
In the world of deniers, the suffering of real human beings is reduced to cynical wordplay and harassment. Denying is an assault on memory, truth, and human dignity.