21505

21,505 is an odd composite number composed of four prime numbers multiplied together.

What does the number 21505 look like?

This visualization shows the relationship between its 4 prime factors (large circles) and 16 divisors.

21505 is an odd composite number. It is composed of four distinct prime numbers multiplied together. It has a total of sixteen divisors.

Prime factorization of 21505:

5 × 11 × 17 × 23

See below for interesting mathematical facts about the number 21505 from the Numbermatics database.


Names of 21505

  • Cardinal: 21505 can be written as Twenty-one thousand, five hundred five.

Scientific notation

  • Scientific notation: 2.1505 × 104

Factors of 21505

  • Number of distinct prime factors ω(n): 4
  • Total number of prime factors Ω(n): 4
  • Sum of prime factors: 56

Divisors of 21505

  • Number of divisors d(n): 16
  • Complete list of divisors:
  • Sum of all divisors σ(n): 31104
  • Sum of proper divisors (its aliquot sum) s(n): 9599
  • 21505 is a deficient number, because the sum of its proper divisors (9599) is less than itself. Its deficiency is 11906

Bases of 21505

  • Binary: 1010100000000012
  • Hexadecimal: 0x5401
  • Base-36: GLD

Squares and roots of 21505

  • 21505 squared (215052) is 462465025
  • 21505 cubed (215053) is 9945310362625
  • The square root of 21505 is 146.6458318535
  • The cube root of 21505 is 27.8086442073

Scales and comparisons

How big is 21505?
  • 21,505 seconds is equal to 5 hours, 58 minutes, 25 seconds.
  • To count from 1 to 21,505 would take you about five 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 21505 cubic inches would be around 2.3 feet tall.

Recreational maths with 21505

  • 21505 backwards is 50512
  • The number of decimal digits it has is: 5
  • The sum of 21505's digits is 13
  • More coming soon!

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"Number 21505 - Facts about the integer". Numbermatics.com. 2024. Web. 28 March 2024.

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Numbermatics. (2024). Number 21505 - Facts about the integer. Retrieved 28 March 2024, from https://numbermatics.com/n/21505/

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The information we have on file for 21505 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 21505, math, Factors of 21505, curriculum, school, college, exams, university, Prime factorization of 21505, STEM, science, technology, engineering, physics, economics, calculator, twenty-one thousand, five hundred five.

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