"Unlucky Number" often refers to the number 13, which is considered unlucky in many cultures. This superstition may stem from various historical and religious beliefs, such as the Last Supper, where Judas, the betrayer of Jesus, was the 13th guest. As a result, many people avoid the number in daily life, such as skipping the 13th floor in buildings. In addition to 13, other numbers can also be seen as unlucky in different cultures. For example, in some Asian cultures, the number 4 is avoided because it sounds like the word for "death." These beliefs can influence various aspects of life, including architecture and personal choices.