Numerology is any belief in divine, mystical or other special relationship between a number and some coinciding events. It has many systems and traditions and beliefs. Numerology and numerological divination by systems such as isopsephy were popular among early mathematicians, but are no longer considered part of mathematics and are regarded as pseudomathematics or pseudoscience by modern scientists. Today, numerology is often associated with the paranormal, alongside astrology and similar divinatory arts.