2. It has been important to practically all major religions.
The Old Testament describes how God made the world in six days and rested on the seventh, laying the groundwork for the current seven-day workweek. The Holy Trinity and the four corners of the Earth are united in the New Testament by the number seven.
The Book of Revelation also makes use of the number seven (seven churches, seven angels, seven seals, seven trumpets, and seven stars). The Kaaba in Mecca, the holiest monument in Islam, is circled seven times by Muslim pilgrims. The Koran mentions seven heavenly realms. Hinduism recognizes seven higher worlds and seven lower worlds, while Buddhism recognizes the newborn Buddha rising and moving in seven directions.
3. It has magical qualities and is connected to good fortune.
Numerous myths and pieces of folklore center around the number seven, which also serves as the symbol for the slot machine jackpot. For instance, traditions concerning the seventh son of a seventh son existed in many cultures, endowing him with both good and bad magical abilities (e.g., the child was believed to have healing powers according to Irish folklore).
4. It corresponds to our memory capacity.
George Miller of Harvard University established that the average person can hold seven pieces of knowledge in their short-term memory in 1956 in what is now regarded as one of the classic works in psychology. Due to the fact that seven digits is the maximum number of digits that the majority of people can remember (although cell phones have eliminated the need to remember anyone’s phone number, even our own), phone numbers in the U.S. and many other countries typically have seven digits (area code excepted).