405

405 is an odd composite number composed of two prime numbers multiplied together.

What does the number 405 look like?

This visualization shows the relationship between its 2 prime factors (large circles) and 10 divisors.

405 is an odd composite number. It is composed of two distinct prime numbers multiplied together. It has a total of ten divisors.

Prime factorization of 405:

3⁴ × 5

(3 × 3 × 3 × 3 × 5)

See below for interesting mathematical facts about the number 405 from the Numbermatics database.

Names of 405

Cardinal: 405 can be written as Four hundred five.

Scientific notation

Scientific notation: 4.05 × 10²

Factors of 405

Number of distinct prime factors ω(n): 2
Total number of prime factors Ω(n): 5
Sum of prime factors: 8

Divisors of 405

Number of divisors d(n): 10
Complete list of divisors:
1 3 5 9 15 27 45 81 135 405
Sum of all divisors σ(n): 726
Sum of proper divisors (its aliquot sum) s(n): 321
405 is a deficient number, because the sum of its proper divisors (321) is less than itself. Its deficiency is 84

Bases of 405

Binary: 110010101₂
Hexadecimal: 0x195
Base-36: B9

Squares and roots of 405

405 squared (405²) is 164025
405 cubed (405³) is 66430125
The square root of 405 is 20.1246117975
The cube root of 405 is 7.3986362229

Scales and comparisons

How big is 405?

405 seconds is equal to 6 minutes, 45 seconds.
To count from 1 to 405 would take you about three 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 405 cubic inches would be around 0.6 feet tall.

Recreational maths with 405

405 backwards is 504
405 is a Harshad number.
The number of decimal digits it has is: 3
The sum of 405's digits is 9
More coming soon!

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The information we have on file for 405 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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