640

640 is an even composite number composed of two prime numbers multiplied together.

What does the number 640 look like?

This visualization shows the relationship between its 2 prime factors (large circles) and 16 divisors.

640 is an even composite number. It is composed of two distinct prime numbers multiplied together. It has a total of sixteen divisors.

Prime factorization of 640:

27 × 5

(2 × 2 × 2 × 2 × 2 × 2 × 2 × 5)

See below for interesting mathematical facts about the number 640 from the Numbermatics database.

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Names Factors Divisors Scales Roots Fun

Names of 640

  • Cardinal: 640 can be written as Six hundred forty.

Scientific notation

  • Scientific notation: 6.4 × 102

Factors of 640

  • Number of distinct prime factors ω(n): 2
  • Total number of prime factors Ω(n): 8
  • Sum of prime factors: 7

Divisors of 640

  • Number of divisors d(n): 16
  • Complete list of divisors:
  • Sum of all divisors σ(n): 1530
  • Sum of proper divisors (its aliquot sum) s(n): 890
  • 640 is an abundant number, because the sum of its proper divisors (890) is greater than itself. Its abundance is 250

Bases of 640

  • Binary: 10100000002
  • Hexadecimal: 0x280
  • Base-36: HS

Squares and roots of 640

  • 640 squared (6402) is 409600
  • 640 cubed (6403) is 262144000
  • The square root of 640 is 25.2982212813
  • The cube root of 640 is 8.6177387601

Scales and comparisons

How big is 640?
  • 640 seconds is equal to 10 minutes, 40 seconds.
  • To count from 1 to 640 would take you about five minutes.

    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 640 cubic inches would be around 0.7 feet tall.

Recreational maths with 640

  • 640 backwards is 046
  • 640 is a Harshad number.
  • The number of decimal digits it has is: 3
  • The sum of 640's digits is 10
  • More coming soon!

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The information we have on file for 640 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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