Talks to Watch

5040 and other Anti-Prime Numbers - Numberphile

2.4M views · Jul 6, 2016 · 13:38 · 1 HN recommender · 4 mentions · discussed 2018–2024

Numberphile's James Grime discusses highly composite numbers, nicknamed anti-primes, which have more factors than any smaller number, using 5040 as the central example. It touches on Plato and Ramanujan.

Why Hacker News points people here: HN points to it whenever highly divisible numbers matter, such as sharding, base 12, time units and music.

“Here is a GREAT video on these 'anti-prime' numbers”HN comment, 2018

What Hacker News said 4

Strongly recommendsBalgairMay 2018

“Here is a GREAT video on these 'anti-prime' numbers”

Explains anti-prime (highly composite) numbers.

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Numbers like 24, 60, and 360 are 'highly composite numbers'. Here is a GREAT video on these 'anti-prime' numbers : this video These anti-prime numbers were studied first by Ramanujan (of course) and conditions are that: 1) The prime factors must be consecutive (2^n X 3^m not 2^n X 5^m) 2) The powers of the prime factors must be deceasing as the prime number increases (2^4 X 3^3 not 2^1 X 3^5) 3) The numbers end with the the highest prime to the highest prime (2^4 X 3^1 not 2^3 X 3^2). Except for the numbers 2 and 4. More here: link

in “The fifth hyperfactorial: 5⁵×4⁴×3³×2²×1¹=86400000 milliseconds is exactly 1 day” · view on HN
Cites itinfogulchOct 2021

“Numberphile made a video about "highly composite numbers" / "anti-primes", which are numbers that have more factors than all smaller numbers.”

Numberphile video on anti-primes, numbers with more factors than smaller ones.

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Numberphile made a video about "highly composite numbers" / "anti-primes", which are numbers that have more factors than all smaller numbers. this video There is an oeis sequence of them that starts "1, 2, 4, 6, 12, 24, 36, 48, 60, 120, 180, 240, 360, 720, 840...", which notably does not include 480. link

in “Lessons learned from sharding Postgres at Notion” · view on HN
Cites itnikeeeAug 2022

“Numberphile [1] calls them "Anti-Primes".”

Numberphile calls highly composite numbers anti-primes.

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These numbers are called "Highly Composite Numbers" [0]. Basically, it is a series of numbers where each number has more factors than the number before it (and is the first number with that number of factors). As you hinted, they are especially useful if your number system does not have fractions or decimal places and you still want to divide things. You may recognize the beginning of the series: 1 2 4 6 12 24 36 48 60 120 180 240 360 720 Numberphile [1] calls them "Anti-Primes". [0]: link [1]: this video

in “Why 12 notes in Western music?” · view on HN
Cites itwillis936Jan 2024

“12 is a highly factorable number and 10 is not.”

Supports claim that 12 is highly factorable.

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They're all magical because they are small. 12 is a highly factorable number and 10 is not. Ancient Greece was not ignorant of this fact. link this video