# 813

## 813 is an odd composite number composed of two prime numbers multiplied together.

What does the number 813 look like?

This visualization shows the relationship between its 2 prime factors (large circles) and 4 divisors.

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

## Prime factorization of 813:

### 3 × 271

See below for interesting mathematical facts about the number 813 from the Numbermatics database.

### Names of 813

• Cardinal: 813 can be written as Eight hundred thirteen.

### Scientific notation

• Scientific notation: 8.13 × 102

### Factors of 813

• Number of distinct prime factors ω(n): 2
• Total number of prime factors Ω(n): 2
• Sum of prime factors: 274

### Divisors of 813

• Number of divisors d(n): 4
• Complete list of divisors:
• Sum of all divisors σ(n): 1088
• Sum of proper divisors (its aliquot sum) s(n): 275
• 813 is a deficient number, because the sum of its proper divisors (275) is less than itself. Its deficiency is 538

### Bases of 813

• Binary: 11001011012
• Base-36: ML

### Squares and roots of 813

• 813 squared (8132) is 660969
• 813 cubed (8133) is 537367797
• The square root of 813 is 28.5131548589
• The cube root of 813 is 9.3331916079

### Scales and comparisons

How big is 813?
• 813 seconds is equal to 13 minutes, 33 seconds.
• To count from 1 to 813 would take you about six 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 813 cubic inches would be around 0.8 feet tall.

### Recreational maths with 813

• 813 backwards is 318
• The number of decimal digits it has is: 3
• The sum of 813's digits is 12
• More coming soon!