11991

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:
1 3 7 21 571 1713 3997 11991
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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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!

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