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
  • Hexadecimal: 0x32D
  • 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!

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The information we have on file for 813 includes mathematical data and numerical statistics calculated using standard algorithms and methods. We are adding more all the time. If there are any features you would like to see, please contact us. Information provided for educational use, intellectual curiosity and fun!

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