# 840

## 840 is an even composite number composed of four prime numbers multiplied together.

What does the number 840 look like?

This visualization shows the relationship between its 4 prime factors (large circles) and 32 divisors.

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

## Prime factorization of 840:

### 23 × 3 × 5 × 7

(2 × 2 × 2 × 3 × 5 × 7)

See below for interesting mathematical facts about the number 840 from the Numbermatics database.

### Names of 840

• Cardinal: 840 can be written as Eight hundred forty.

### Scientific notation

• Scientific notation: 8.4 × 102

### Factors of 840

• Number of distinct prime factors ω(n): 4
• Total number of prime factors Ω(n): 6
• Sum of prime factors: 17

### Divisors of 840

• Number of divisors d(n): 32
• Complete list of divisors:
• Sum of all divisors σ(n): 2880
• Sum of proper divisors (its aliquot sum) s(n): 2040
• 840 is an abundant number, because the sum of its proper divisors (2040) is greater than itself. Its abundance is 1200

### Bases of 840

• Binary: 11010010002
• Base-36: NC

### Squares and roots of 840

• 840 squared (8402) is 705600
• 840 cubed (8403) is 592704000
• The square root of 840 is 28.9827534923
• The cube root of 840 is 9.4353879607

### Scales and comparisons

How big is 840?
• 840 seconds is equal to 14 minutes.
• To count from 1 to 840 would take you about seven minutes.

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 840 cubic inches would be around 0.8 feet tall.

### Recreational maths with 840

• 840 backwards is 048
• 840 is a Harshad number.
• The number of decimal digits it has is: 3
• The sum of 840's digits is 12
• More coming soon!