# 21105

## 21,105 is an odd composite number composed of four prime numbers multiplied together.

What does the number 21105 look like?

This visualization shows the relationship between its 4 prime factors (large circles) and 24 divisors.

21105 is an odd composite number. It is composed of four distinct prime numbers multiplied together. It has a total of twenty-four divisors.

## Prime factorization of 21105:

### 32 × 5 × 7 × 67

(3 × 3 × 5 × 7 × 67)

See below for interesting mathematical facts about the number 21105 from the Numbermatics database.

### Names of 21105

• Cardinal: 21105 can be written as Twenty-one thousand, one hundred five.

### Scientific notation

• Scientific notation: 2.1105 × 104

### Factors of 21105

• Number of distinct prime factors ω(n): 4
• Total number of prime factors Ω(n): 5
• Sum of prime factors: 82

### Divisors of 21105

• Number of divisors d(n): 24
• Complete list of divisors:
• Sum of all divisors σ(n): 42432
• Sum of proper divisors (its aliquot sum) s(n): 21327
• 21105 is an abundant number, because the sum of its proper divisors (21327) is greater than itself. Its abundance is 222

### Bases of 21105

• Binary: 1010010011100012
• Base-36: GA9

### Squares and roots of 21105

• 21105 squared (211052) is 445421025
• 21105 cubed (211053) is 9400610732625
• The square root of 21105 is 145.2756001535
• The cube root of 21105 is 27.6351474089

### Scales and comparisons

How big is 21105?
• 21,105 seconds is equal to 5 hours, 51 minutes, 45 seconds.
• To count from 1 to 21,105 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 21105 cubic inches would be around 2.3 feet tall.

### Recreational maths with 21105

• 21105 backwards is 50112
• 21105 is a Harshad number.
• The number of decimal digits it has is: 5
• The sum of 21105's digits is 9
• More coming soon!