11,991 is an odd composite number composed of three prime numbers multiplied together.

What does the number 11991 look like?

This visualization shows the relationship between its 3 prime factors (large circles) and 8 divisors.

11991 is an odd composite number. It is composed of three distinct prime numbers multiplied together. It has a total of eight divisors.

Prime factorization of 11991:

3 × 7 × 571

See below for interesting mathematical facts about the number 11991 from the Numbermatics database.

Names of 11991

  • Cardinal: 11991 can be written as Eleven thousand, nine hundred ninety-one.

Scientific notation

  • Scientific notation: 1.1991 × 104

Factors of 11991

  • Number of distinct prime factors ω(n): 3
  • Total number of prime factors Ω(n): 3
  • Sum of prime factors: 581

Divisors of 11991

  • Number of divisors d(n): 8
  • Complete list of divisors:
  • Sum of all divisors σ(n): 18304
  • Sum of proper divisors (its aliquot sum) s(n): 6313
  • 11991 is a deficient number, because the sum of its proper divisors (6313) is less than itself. Its deficiency is 5678

Bases of 11991

  • Binary: 101110110101112
  • Hexadecimal: 0x2ED7
  • Base-36: 993

Squares and roots of 11991

  • 11991 squared (119912) is 143784081
  • 11991 cubed (119913) is 1724114915271
  • The square root of 11991 is 109.5034246039
  • The cube root of 11991 is 22.8885598485

Scales and comparisons

How big is 11991?
  • 11,991 seconds is equal to 3 hours, 19 minutes, 51 seconds.
  • To count from 1 to 11,991 would take you about three 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 11991 cubic inches would be around 1.9 feet tall.

Recreational maths with 11991

  • 11991 backwards is 19911
  • 11991 is a Harshad number.
  • The number of decimal digits it has is: 5
  • The sum of 11991's digits is 21
  • More coming soon!

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"Number 11991 - Facts about the integer". Numbermatics.com. 2023. Web. 30 March 2023.

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Numbermatics. (2023). Number 11991 - Facts about the integer. Retrieved 30 March 2023, from https://numbermatics.com/n/11991/

Chicago style:
Numbermatics. 2023. "Number 11991 - Facts about the integer". https://numbermatics.com/n/11991/

The information we have on file for 11991 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!

Keywords: Divisors of 11991, math, Factors of 11991, curriculum, school, college, exams, university, Prime factorization of 11991, STEM, science, technology, engineering, physics, economics, calculator, eleven thousand, nine hundred ninety-one.

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