21391721

21,391,721 is an odd composite number composed of four prime numbers multiplied together.

What does the number 21391721 look like?

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

21391721 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 21391721:

13 × 47 × 157 × 223

See below for interesting mathematical facts about the number 21391721 from the Numbermatics database.

Names of 21391721

Cardinal: 21391721 can be written as Twenty-one million, three hundred ninety-one thousand, seven hundred twenty-one.

Scientific notation

Scientific notation: 2.1391721 × 10⁷

Factors of 21391721

Number of distinct prime factors ω(n): 4
Total number of prime factors Ω(n): 4
Sum of prime factors: 440

Divisors of 21391721

Number of divisors d(n): 16
Complete list of divisors:
1 13 47 157 223 611 2041 2899 7379 10481 35011 95927 136253 455143 1645517 21391721
Sum of all divisors σ(n): 23783424
Sum of proper divisors (its aliquot sum) s(n): 2391703
21391721 is a deficient number, because the sum of its proper divisors (2391703) is less than itself. Its deficiency is 19000018

Bases of 21391721

Binary: 1010001100110100101101001₂
Hexadecimal: 0x1466969
Base-36: CQHYH

Squares and roots of 21391721

21391721 squared (21391721²) is 457605727341841
21391721 cubed (21391721³) is 9788974047298734298361
The square root of 21391721 is 4625.1184849687
The cube root of 21391721 is 277.5973026741

Scales and comparisons

How big is 21391721?

21,391,721 seconds is equal to 35 weeks, 2 days, 14 hours, 8 minutes, 41 seconds.
To count from 1 to 21,391,721 would take you about nine 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 21391721 cubic inches would be around 23.1 feet tall.

Recreational maths with 21391721

21391721 backwards is 12719312
The number of decimal digits it has is: 8
The sum of 21391721's digits is 26
More coming soon!

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The information we have on file for 21391721 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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