# 18

## 18 is an even composite number composed of two prime numbers multiplied together.

What does the number 18 look like?

This visualization shows the relationship between its 2 prime factors (large circles) and 6 divisors.

18 is an even composite number. It is composed of two distinct prime numbers multiplied together. It has a total of six divisors.

## Prime factorization of 18:

### 2 × 32

(2 × 3 × 3)

See below for interesting mathematical facts about the number 18 from the Numbermatics database.

### Names of 18

• Cardinal: 18 can be written as Eighteen.

### Scientific notation

• Scientific notation: 1.8 × 101

### Factors of 18

• Number of distinct prime factors ω(n): 2
• Total number of prime factors Ω(n): 3
• Sum of prime factors: 5

### Divisors of 18

• Number of divisors d(n): 6
• Complete list of divisors:
• Sum of all divisors σ(n): 39
• Sum of proper divisors (its aliquot sum) s(n): 21
• 18 is an abundant number, because the sum of its proper divisors (21) is greater than itself. Its abundance is 3

### Bases of 18

• Binary: 100102
• Base-36: I

### Squares and roots of 18

• 18 squared (182) is 324
• 18 cubed (183) is 5832
• The square root of 18 is 4.2426406871
• The cube root of 18 is 2.6207413943

### Scales and comparisons

How big is 18?
• A cube with a volume of 18 cubic inches would be around 0.2 feet tall.

### Recreational maths with 18

• 18 backwards is 81
• 18 is a Harshad number.
• The number of decimal digits it has is: 2
• The sum of 18's digits is 9
• More coming soon!

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The information we have on file for 18 includes mathematical data and numerical statistics calculated using standard algorithms and methods. We are adding more all the time. If there are any features you would like to see, please contact us. Information provided for educational use, intellectual curiosity and fun!

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