# 20405

## 20,405 is an odd composite number composed of four prime numbers multiplied together.

What does the number 20405 look like?

This visualization shows the relationship between its 4 prime factors (large circles) and 16 divisors.

20405 is an odd composite number. It is composed of four distinct prime numbers multiplied together. It has a total of sixteen divisors.

## Prime factorization of 20405:

### 5 × 7 × 11 × 53

See below for interesting mathematical facts about the number 20405 from the Numbermatics database.

### Names of 20405

• Cardinal: 20405 can be written as Twenty thousand, four hundred five.

### Scientific notation

• Scientific notation: 2.0405 × 104

### Factors of 20405

• Number of distinct prime factors ω(n): 4
• Total number of prime factors Ω(n): 4
• Sum of prime factors: 76

### Divisors of 20405

• Number of divisors d(n): 16
• Complete list of divisors:
• Sum of all divisors σ(n): 31104
• Sum of proper divisors (its aliquot sum) s(n): 10699
• 20405 is a deficient number, because the sum of its proper divisors (10699) is less than itself. Its deficiency is 9706

### Bases of 20405

• Binary: 1001111101101012
• Base-36: FQT

### Squares and roots of 20405

• 20405 squared (204052) is 416364025
• 20405 cubed (204053) is 8495907930125
• The square root of 20405 is 142.8460709995
• The cube root of 20405 is 27.3261763269

### Scales and comparisons

How big is 20405?
• 20,405 seconds is equal to 5 hours, 40 minutes, 5 seconds.
• To count from 1 to 20,405 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 20405 cubic inches would be around 2.3 feet tall.

### Recreational maths with 20405

• 20405 backwards is 50402
• 20405 is a Harshad number.
• The number of decimal digits it has is: 5
• The sum of 20405's digits is 11
• More coming soon!