https://en.wikipedia.org/wiki/Tzadikim_Nistarim
As a mystical concept, the number 36 is even more intriguing. It is said that at all times there are 36 special people in the world, and that were it not for them, all of them, if even one of them was missing, the world would come to an end. The two Hebrew letters for 36 are the lamed, which is 30, and the vav, which is 6. Therefore, these 36 are referred to as the Lamed-Vav Tzadikim. This widely-held belief, this most unusual Jewish concept is based on a Talmudic statement to the effect that in every generation 36 righteous "greet the Shekhinah", the Divine Presence (Tractate Sanhedrin 97b; Tractate Sukkah 45b).
The Shekhina(h) (also spelled Shekina(h), Schechina(h), or Shechina(h)) (Biblical Hebrew: שכינה) is the English transliteration of a Hebrew word meaning "dwelling" or "settling" and denotes the dwelling or settling of the divine presence of God. The Shekhinah is the feminine aspect of Divinity, also referred to as the Divine Presence. (https://en.wikipedia.org/wiki/Shekhinah)
