The Tetragrammoton (YKVK) has a numerical value of 26, but the letters Hey (ה) and Vav (ו) each can be spelled three different ways: (Note: "K" here indicates the letter Hey.)
The Heys: The Vovs: The Yud:
HY= 15; VYV = 22; YVD= 20
HA = 6; VAV = 13;
HH = 10; VV = 12
Thus the YKVK can also be spelled differently depending on the spellings of Hey (ה) and Vav (ו).
There are four general expansions of YKVK.
The first is YUD HY VYV HY (יו"ד ה"י וי"ו ה"י) and is expanded with Yuds. This is the name A"V (ע"ב) its numerical value is 72
The second is YUD HY VAV HY (יו"ד ה"י וא"ו ה"י) and is expanded with Yuds and an Aleph. This is the name SA"G (ס"ג) its numerical value is 63.
The third is YUD HA VAV HA (יו"ד ה"א וא"ו ה"א) and is expanded with Alefs. This is the name M"AH (מ"ה) its numerical value 45.
The fourth is YUD HH VV HH (יו"ד ה"ה ו"ו ה"ה). This is the name B"AN (ב"ן), its numerical value is 52. It is called Ban (ב"ן) though the proper form is Nav (נ"ב), the greater value preceding the lesser. This is to avoid the confusion with Av (ע"ב).
These four spellings-out (Av-72, Sag-63, Mah-45, and Ban-52) correspond to the five Profiles (Partzufim) which are represented by the name YKVK;
72 is Keter and Chochmah, represented by the tip and body of the Yod (י).
63 points to Binah, represented by the first Hey (ה).
45 corresponds to the six Sefirot of Zeir Anpin (Miniature Face) represented by the Vav (ו). These are the emotions (midos).
52 corresponds to Malchut, represented by the final Hey (ה).
Together, they correspond to all 10 Sfirot.