What is 81?

81 is a natural number that comes after 80 and before 82. It is an odd number, meaning it is not divisible evenly by 2.

In mathematics, 81 is a perfect square, as it can be expressed as the square of 9 (9 * 9 = 81). It is also a composite number, as it has factors other than 1 and itself. The factors of 81 are 1, 3, 9, 27, and 81.

81 is highly symmetrical, as its digits are mirror images of each other. It is often associated with concepts of balance and harmony.

In terms of measurements, 81 can represent different quantities depending on the unit of measurement used. For example, it can represent an area of 81 square units or a distance of 81 units.

In various fields, 81 may hold significance. In religious texts, it may represent spiritual completion or a significant age. In sports, it has been worn as a jersey number by notable athletes in basketball, baseball, and other sports.

Overall, 81 is a number with various mathematical properties and cultural references, which can hold different meanings depending on the context.