**What Is 9:**

9 is the natural number following eight and preceding 10. In Mathematics, 9 is the square of 3.

9 has several interesting properties. It is the only positive integer that is more than a sum of its digits (4+5=9). And it’s also the only number that is one less than a product of its digits (6×3=18-1=17).

In base 10, 9 is a two-digit number, and in the binary form, it consists of only 1s (10011). Nine frequently appears in mathematical sequences and series, notably in the Fibonacci sequence. Curiously, the sum of all nine squares (1+4++16+25+36+49+64+81) is equal to 144 (=12×12).

In Arabic and other cultures, nine was often used to symbolize something complete or perfect. However, this thinking was not universal, and many different cultures chose ten symbols instead (the Chinese use specific symbols such as coins for numbers 8 and 10).

The grammatical symbol ‘nine’ has its character in most scripts of south Asia, including Devanagari, Bengali, Gurmukhi. It is called Nava in Sanskrit and pañca in Hindi. The same word is also used for the Scandinavian “9” letter ‘ni’. In Japan’s system of counting money, there are two distinct symbols: 九百 (900,) and 九千 (9,000).

Some collectors specialize in collecting objects with a nine theme (such as sterling silver items or postcards), while others might focus on anything with the number displayed prominently. Some examples of these unusual displays of the digit nine are: Nine dots in a cube, nine playing cards laid out with no space between them, nine cannonballs stacked together, or nine tacks stuck into a corkboard.

**What is 9 in measurement:**

A unit of measurement is a standardized procedure for measuring physical or chemical quantities. There are many different units of measurement, but they all fall into one of two categories: absolute and derived. Total units measure an intrinsic property of the object being measured, while derived units are a combination or multiple of other teams.

The most common unit of measurement is the metre, which is defined as the distance travelled by light in a vacuum in 1/299,792,458th of a second. Other absolute units include the kilogram (mass), ampere (electric current), kelvin (temperature) and candela (luminous intensity). Derived units have litres (volume), newtons (force) and watts (power).

Some units of measurement have a unique name, such as the tonne (metric ton), gallon (imperial gallon) and bar (pressure). Others are called multiples of other units, such as the millilitre (thousandth of a litre) and the megawatt (million watts). In most cases, these derived units can be converted into absolute units by multiplying them by a fixed factor. For example, 1 litre is equivalent to 1 kilogramme/1000 litres.

Most countries have adopted the metric system as their official system of measurement. This system uses SI units based on the metre, kilogramme, and second. However, some regions still use imperial units based on the foot, stone, and pound.

**9 in religion:**

The number 9 often appears in many cultures as it holds special significance in Hinduism, Buddhism, Jainism, 4 Taoist belief systems (the Four Xiang), Wicca and others. The numbers 3 and 7 are considered necessary due to their association with the divine trinity in some religions. But when multiplied together, they equal 27 – an equally significant figure.

Buddhists believe that the 9th day of any month is significant because it corresponds with a full moon or naamaharan day, i.e. one complete lunar cycle since the beginning of Buddhist Lent (Uposatha/Ullambana). It also is symbolic of the 9th bhumi (enlightenment) attained by all Buddhas.

Nine was considered the most auspicious number in Indian traditions. It is reflected in its representation of Navagrahastakam, or “nine planets”. The navagraha are believed to influence life on earth and be responsible for good or bad fortune. Auspicious dates are determined depending on which planet rules a day.

Suppose one adds each multiple of nine corresponding with a particular planet. In that case, one traces its power over the 360 degrees of an entire circle- that is why it has special significance as being able to encompass everything at once. For instance, if Tuesday’s ruler Mercury is strong, one must plan activities for that daycare because the planet of communication and intelligence rules it.

**What is nine factorial:**

factorial of 9 = 362808 (5 * 4 * 3 * 2 * 1)

the square of 9 is 81, and the square root is 3.

the cube of 9 is 729, and the cube root is 27.