I'm sure you're already aware, but for everyone else's sake:

• Hebrew is both a language and a counting system. This gives us gematria and things of that nature

• Most of the hebrew old testament is lost. What's left is interpreted through the lense of the Talmud. Hilariously enough, the when Greek was becoming the lingua franca of the Mediterranean, the rabbis decided to destroy all jewish texts written in Greek so that the gentiles wouldn't find out about their religious beliefs. Most of the scripture had been lost well before that, but destroying what was left didn't help.

There is a passage in the Torah that reads "ye shall return" in reference to the holy land: the state of Israel. In Hebrew this passage is spelled incorrectly. It's missing a letter. The missing letter also represents the number 6; thus the passage is interpreted by jewish scholars to read, "ye shall return (minus 6)." This is taught to children in israeli schools as a justification for the existence of their ethnostate. It is also the basis for orthodox jewish groups like the neturei karta.

Within the more mystical talmudic and hebrew traditions the number 6 bears a special significance, similar to the the numbers 3, 33, or 7 in Christianity.

Here's a blog that took me all of 35 seconds to find with some more info on this. As someone else here pointed out references to 6million dead go back almost 200 years in America alone. This relates to other kabalistic/talmudic teachings related to demonology and the creation of golemns found in the jewish holy texts; basically the party being cursed has to be told about the curse (whether they're aware or not is irrelevant) and the negative energy/spirit is more powerful with more people knowing, or the more often the curse/name etc. is repeated.

So whenever 6 million people die, this is big medicine to the edomite.