Discover a lot of information on the number 18: properties, mathematical operations, how to write it, symbolism, numerology, representations and many other interesting things!

## Mathematical properties of 18

Is 18 a prime number? No
Is 18 a perfect number? No
Number of divisors 6
List of dividers 1, 2, 3, 6, 9, 18
Sum of divisors 39
Prime factorization 2 x 32
Prime factors 2, 3

## How to write / spell 18 in letters?

In letters, the number 18 is written as: Eighteen. And in other languages? how does it spell?

18 in other languages
Write 18 in english Eighteen
Write 18 in french Dix-huit
Write 18 in spanish Dieciocho
Write 18 in portuguese Dezoito

## Decomposition of the number 18

The number 18 is composed of:

1 iteration of the number 1 : The number 1 (one) represents the uniqueness, the unique, a starting point, a beginning.... Find out more about the number 1

1 iteration of the number 8 : The number 8 (eight) represents power, ambition. It symbolizes balance, realization.... Find out more about the number 8

Other ways to write 18
In letter Eighteen
In roman numeral XVIII
In binary 10010
In octal 22
In US dollars USD 18.00 (\$)
In euros 18,00 EUR (€)
Some related numbers
Previous number 17
Next number 19
Next prime number 19

## Mathematical operations

Operations and solutions
18*2 = 36 The double of 18 is 36
18*3 = 54 The triple of 18 is 54
18/2 = 9 The half of 18 is 9.000000
18/3 = 6 The third of 18 is 6.000000
182 = 324 The square of 18 is 324.000000
183 = 5832 The cube of 18 is 5832.000000
√18 = 4.2426406871193 The square root of 18 is 4.242641
log(18) = 2.8903717578962 The natural (Neperian) logarithm of 18 is 2.890372
log10(18) = 1.2552725051033 The decimal logarithm (base 10) of 18 is 1.255273
sin(18) = -0.75098724677168 The sine of 18 is -0.750987
cos(18) = 0.66031670824408 The cosine of 18 is 0.660317
tan(18) = -1.1373137123377 The tangent of 18 is -1.137314