90

90 is an even composite number composed of three prime numbers multiplied together.

90 is an even composite number. It is composed of three distinct prime numbers multiplied together. It has a total of twelve divisors.

Prime factorization of 90:

2 × 32 × 5

(2 × 3 × 3 × 5)

See below for interesting mathematical facts about the number 90 from the Numbermatics database.

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Names Factors Divisors Scales Roots Fun

Names of 90

  • Cardinal: 90 can be written as Ninety.

Scientific notation

  • Scientific notation: 9 × 101

Factors of 90

  • Number of distinct prime factors ω(n): 3
  • Total number of prime factors Ω(n): 4
  • Sum of prime factors: 10

Divisors of 90

  • Number of divisors d(n): 12
  • Complete list of divisors:
    1 2 3 5 6 9 10 15 18 30 45 90
  • Sum of all divisors σ(n): 234
  • Sum of proper divisors (its aliquot sum) s(n): 144
  • 90 is an abundant number, because the sum of its proper divisors (144) is greater than itself. Its abundance is 54

Bases of 90

  • Binary: 1011010 2
  • Hexadecimal: 0x5a

Squares and roots of 90

  • 90 squared (902) is 8100
  • 90 cubed (903) is 729000
  • The square root of 90 is 9.4868329807
  • The cube root of 90 is 4.4814047465

Scales and comparisons

How big is 90?
  • 90 seconds is equal to 1 minute, 30 seconds.
  • To count from 1 to 90 would take you about forty-five seconds.

    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.

    Note: we do not count involuntary pauses, bathroom breaks or the necessity of sleep in our calculation!

  • A cube with a volume of 90 cubic inches would be around 0.4 feet tall.

Recreational maths with 90

  • 90 backwards is 09
  • 90 is a Harshad number.
  • The number of decimal digits it has is: 2
  • The sum of 90's digits is 9
  • More coming soon!

The information we have on file for 90 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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