The number seven is a natural number that follows six and precedes eight. It is often considered a significant number in various cultures and religions, symbolizing completeness or perfection. For example, there are seven days in a week and seven continents on Earth. In mathematics, seven is classified as a prime number because it can only be divided by one and itself. It is also the fourth Mersenne prime, which is a prime number that can be expressed in the form of 2^p - 1, where p is also a prime number.