Here are some interesting info about the number 7 in relation to Chaldean numerology:
When we divide the number 1 by 7, we get a repeating sequence of the digits 1, 4, 2, 8, 5, and 7. 1/7= 0.142857142857142857142857142857142857… In these sequences, the numbers 3, 6, and 9 (which form a special trio in numerology) do not appear.
When a number with a base number of 7 encounters a number with a base number of 3, it often results in a relationship that may initially seem very good but can evolve into emotional dramas and disputes, or reflect challenging family or partnership karma. Additionally, it can bring stagnation and challenges in other areas (career, finances). In some cases, individuals with such a setup also have very unfavorable energetic connections with the astral. Conversely, in some instances, this relationship represents love, friendship, success, optimism, or even spiritual elevation.
When two sevens meet in a personal numerological chart and do not meet with additional sevens, it often represents a potential for great wisdom.
Individuals with the numbers 6 and 7 often feel a strong mutual attraction at first, too. However, in the long run, such a connection doesn’t fare well, as the seven will try to distance itself and this can irritate the family-oriented six. This creates difficulties in the partnership and can also lead to financial challenges.
The connection between the number 7 and the number 9 is not favorable. However, for a person with the number 7, this relationship is less burdensome than the reverse. In some cases, such a relationship can bring significant power; however, a person with these numbers may become aggressive if they feel threatened.
The number 7 represents the element of water (Moon and Neptune), and its origin is very spiritual. Because of this, it has a great deal of spiritual fire behind it. In the ordinary world, its “watery” side is primarily visible. When two sevens come together, such a connection can therefore become “too cold” and may cause difficulties with fertility.
The Mystery of Numbers, Luck, Worlds and Planets 