7,991 is an odd composite number composed of two prime numbers multiplied together.

What does the number 7991 look like?

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

7991 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 7991:

61 × 131

See below for interesting mathematical facts about the number 7991 from the Numbermatics database.

Names of 7991

  • Cardinal: 7991 can be written as Seven thousand, nine hundred ninety-one.

Scientific notation

  • Scientific notation: 7.991 × 103

Factors of 7991

  • Number of distinct prime factors ω(n): 2
  • Total number of prime factors Ω(n): 2
  • Sum of prime factors: 192

Divisors of 7991

  • Number of divisors d(n): 4
  • Complete list of divisors:
  • Sum of all divisors σ(n): 8184
  • Sum of proper divisors (its aliquot sum) s(n): 193
  • 7991 is a deficient number, because the sum of its proper divisors (193) is less than itself. Its deficiency is 7798

Bases of 7991

  • Binary: 11111001101112
  • Hexadecimal: 0x1F37
  • Base-36: 65Z

Squares and roots of 7991

  • 7991 squared (79912) is 63856081
  • 7991 cubed (79913) is 510273943271
  • The square root of 7991 is 89.3923934125
  • The cube root of 7991 is 19.9924971859

Scales and comparisons

How big is 7991?
  • 7,991 seconds is equal to 2 hours, 13 minutes, 11 seconds.
  • To count from 1 to 7,991 would take you about two 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 7991 cubic inches would be around 1.7 feet tall.

Recreational maths with 7991

  • 7991 backwards is 1997
  • The number of decimal digits it has is: 4
  • The sum of 7991's digits is 26
  • More coming soon!

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The information we have on file for 7991 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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