The number 4 is considered very unlucky by some Chinese cultures as it is associated with death.
In some Western cultures the number 4, however, is associated with creation and birth.
Personality traits of the number 4
The number 4 can suggest practical skills and organisation in people. The number suggests hard work, honesty and enterprise.
Letter numeric values for the number 4
The number 4 is associated with the letter D. It can sometimes also be associated with the letters M and V.
Using the Chaldean method of numerology the number 4 is linked to the letters D, M and T.
In Cantonese the number 4 is pronounced si and the word for death is pronounced sǐ. As a result the number 4 is considered to be unlucky.
In Pure Spirit
Do you find the number 4 tends to be unlucky or have you been in a building which has had the 4th floor ‘omitted’?

For an up-to-date explanation of the metaphysical attributes of numbers in context with current scientific facts, a demonstration of a numerological pattern in number Pi, clusters of numbers especially number 7 and number 4, and the demonstration of living successful authentic lives see my book “Invisible Cloak – Know Thyself” (http://www.sumuniversal.com).
Understanding. Learning. Lesson afoot. Clear. Also humble.
This is just my surmise and may not be correct for you.