# 21390

## 21,390 is an even composite number composed of five prime numbers multiplied together.

What does the number 21390 look like?

This visualization shows the relationship between its 5 prime factors (large circles) and 32 divisors.

21390 is an even composite number. It is composed of five distinct prime numbers multiplied together. It has a total of thirty-two divisors.

## Prime factorization of 21390:

### 2 × 3 × 5 × 23 × 31

See below for interesting mathematical facts about the number 21390 from the Numbermatics database.

### Names of 21390

• Cardinal: 21390 can be written as Twenty-one thousand, three hundred ninety.

### Scientific notation

• Scientific notation: 2.139 × 104

### Factors of 21390

• Number of distinct prime factors ω(n): 5
• Total number of prime factors Ω(n): 5
• Sum of prime factors: 64

### Divisors of 21390

• Number of divisors d(n): 32
• Complete list of divisors:
• Sum of all divisors σ(n): 55296
• Sum of proper divisors (its aliquot sum) s(n): 33906
• 21390 is an abundant number, because the sum of its proper divisors (33906) is greater than itself. Its abundance is 12516

### Bases of 21390

• Binary: 1010011100011102
• Base-36: GI6

### Squares and roots of 21390

• 21390 squared (213902) is 457532100
• 21390 cubed (213903) is 9786611619000
• The square root of 21390 is 146.2532050929
• The cube root of 21390 is 27.7589858085

### Scales and comparisons

How big is 21390?
• 21,390 seconds is equal to 5 hours, 56 minutes, 30 seconds.
• To count from 1 to 21,390 would take you about five hours.

This is a very rough estimate, based on a speaking rate of half a second every third order of magnitude. If you speak quickly, you could probably say any randomly-chosen number between one and a thousand in around half a second. Very big numbers obviously take longer to say, so we add half a second for every extra x1000. (We do not count involuntary pauses, bathroom breaks or the necessity of sleep in our calculation!)

• A cube with a volume of 21390 cubic inches would be around 2.3 feet tall.

### Recreational maths with 21390

• 21390 backwards is 09312
• 21390 is a Harshad number.
• The number of decimal digits it has is: 5
• The sum of 21390's digits is 15
• More coming soon!