21018642721

Names of 21018642721

• Cardinal: 21018642721 can be written as Twenty-one billion, eighteen million, six hundred forty-two thousand, seven hundred twenty-one.

Scientific notation

• Scientific notation: 2.1018642721 × 10¹⁰

Factors of 21018642721

• Number of distinct prime factors ω(n): 1
• Total number of prime factors Ω(n): 1
• Sum of prime factors: 21018642721

Divisors of 21018642721

• Number of divisors d(n): 2
• Complete list of divisors:
  1 21018642721
• Sum of all divisors σ(n): 21018642722
• Sum of proper divisors (its aliquot sum) s(n): 1
• 21018642721 is a deficient number, because the sum of its proper divisors (1) is less than itself. Its deficiency is 21018642720

Bases of 21018642721

• Binary: 10011100100110011110000100100100001₂
• Hexadecimal: 0x4E4CF0921
• Base-36: 9NLYGIP

Squares and roots of 21018642721

• 21018642721 squared (21018642721²) is 441783341833046283841
• 21018642721 cubed (21018642721³) is 9285686222078213071110734571361
• The square root of 21018642721 is 144978.0766909259
• The cube root of 21018642721 is 2759.7403452871

Scales and comparisons

• 21,018,642,721 seconds is equal to 668 years, 17 weeks, 7 hours, 52 minutes, 1 second.
• To count from 1 to 21,018,642,721 would take you about one thousand, three hundred thirty-six years!

  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 21018642721 cubic inches would be around 230 feet tall.

Recreational maths with 21018642721

• 21018642721 backwards is 12724681012
• The number of decimal digits it has is: 11
• The sum of 21018642721's digits is 34
• More coming soon!