View source for 40,000

{{Redirect|40k|the tabletop game|Warhammer 40,000|the isotope <sup>40</sup>K|Potassium-40}}
{{Infobox number
| number = 40000	
|divisor=35 total}}

'''40,000''' ('''forty thousand''') is the [[natural number]] that comes after 39,999 and before 40,001. It is the square of 200.

==Selected numbers in the range 40001–49999==
===40001 to 40999===
* '''40320''' = smallest [[factorial]] (8!) that is not a [[highly composite number]]
* '''40425''' = [[square pyramidal number]]
* '''40585''' = largest [[factorion]]<ref>{{Cite web|url=https://oeis.org/A014080|title=Sloane's A014080 : Factorions|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-15}}</ref>
* '''40678''' = [[pentagonal pyramidal number]]
* '''40755''' = the smallest number >1 to be a [[Triangular number]], [[Pentagonal number]], and a [[Hexagonal number]].<ref>{{Cite web |title=A046180 - OEIS |url=https://oeis.org/A046180 |access-date=2024-12-18 |website=oeis.org}}</ref> Additionally, it's a 390-gonal, 4077-gonal, and 13586-gonal number.<ref>{{cite OEIS|A000217|Triangular numbers}}</ref><ref>{{cite OEIS|A000326|Pentagonal numbers}}</ref><ref>{{cite OEIS|A000384|Hexagonal numbers}}</ref>
* '''40804''' = [[palindromic number|palindromic]] square

===41000 to 41999===
* '''41041''' = [[Carmichael number]]<ref name="Sloane's A002997">{{Cite web|url=https://oeis.org/A002997|title=Sloane's A002997 : Carmichael numbers|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-15}}</ref>
* '''41472''' = 3-[[smooth number]], number of reduced trees with 24 nodes<ref>{{cite OEIS|A000014|Number of series-reduced trees with n nodes}}</ref>
* '''41586''' = [[oeis:A006318|Large Schröder number]]
* '''41616''' = [[triangular square number]]<ref>{{Cite web|url=https://oeis.org/A001110|title=Sloane's A001110 : Square triangular numbers|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-15}}</ref>
* '''41835''' = [[Motzkin number]]<ref>{{Cite web|url=https://oeis.org/A001006|title=Sloane's A001006 : Motzkin numbers|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-15}}</ref>
* '''41841''' = 1/41841 = 0.0000239 is a repeating decimal with period 7

===42000 to 42999===
* '''42680''' = [[octahedral number]]<ref>{{Cite web|url=https://oeis.org/A005900|title=Sloane's A005900 : Octahedral numbers|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-15}}</ref>
* '''42875''' = 35<sup>3</sup>
* '''42925''' = [[square pyramidal number]]

===43000 to 43999===
* '''43261''' = [[Markov number]]<ref>{{Cite web|url=https://oeis.org/A002559|title=Sloane's A002559 : Markoff (or Markov) numbers|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-15}}</ref>
* '''43380''' = number of nets of a dodecahedron
* '''43390''' = number of primes <math>\leq 2^{19}</math>.<ref>{{cite OEIS|A007053|2=Number of primes <= 2^n}}</ref>
* '''43560''' = pentagonal pyramidal number
* '''43691''' = [[Wagstaff prime]]<ref>{{Cite OEIS|A000979|Wagstaff primes}}</ref>
* '''43777''' = smallest member of a prime sextuplet

===44000 to 44999===
* '''44044''' = palindrome of [[79 (number)|79]] after 6 iterations of the "reverse and add" iterative process<ref>{{cite web|url=http://jasondoucette.com/pal/79|title=Reversal-Addition Palindrome Test on 79}}</ref>
* '''44100''' = sum of the cubes of the first 20 positive integers [[44,100 Hz]] is a common [[sampling frequency]] in digital audio (and is the standard for [[compact disc]]s).
* '''44444''' = [[repdigit]]
* '''44583''' = number of partitions of 41<ref>{{cite OEIS|A000041|a(n) is the number of partitions of n (the partition numbers)}}</ref>
* '''44721''' = smallest positive integer such that the expression {{sfrac|1|''n''}} − {{sfrac|1|''n'' + 2}} ≤ 10<sup>−9</sup>
* '''44724''' = maximum number of days in which a human being has been verified to live ([[Jeanne Calment]]).<ref name="The Promise of Immortality">{{cite book |last1=Amzallag |first1=William |title=The Promise of Immortality |url=https://books.google.com/books?id=AQI0DQAAQBAJ&dq=44724+days+old&pg=PA12|page=12 |date=22 September 2016 |publisher=Varegus Publishing |isbn=978-2-9558558-1-2 |access-date=September 22, 2016}}</ref>
* '''44944''' = palindromic square

===45000 to 45999===

* '''45360''' = 26th [[highly composite number]];<ref>{{Cite OEIS|A002182|Highly composite numbers}}</ref> smallest number with exactly 100 factors (including one and itself)

===46000 to 46999===
* '''46080''' = [[double factorial]] of 12
* '''46233''' = sum of the first eight factorials
* '''46249''' = 2nd number that can be written as <math>a^2+b!</math> in 3 ways<ref>{{cite OEIS|A359013|Numbers k that can be written as the sum of a perfect square and a factorial in exactly 3 distinct ways}}</ref>
* '''46368''' = [[Fibonacci number]]<ref>{{Cite OEIS|A000045|Fibonacci numbers}}</ref>
* '''46656''' = 216{{sup|2}} = 36{{sup|3}} = 6<sup>6</sup>, 3-[[smooth number]]
* '''46657''' = Carmichael number<ref name="Sloane's A002997" />
* '''46972''' = number of [[prime knots]] with 14 crossings

===47000 to 47999===
* '''47058''' = [[primary pseudoperfect number]]<ref>{{Cite OEIS|A054377|Primary pseudoperfect numbers}}</ref>
* '''47160''' = 10-th derivative of x<sup>x</sup> at x=1<ref>{{cite OEIS|A005727|2=n-th derivative of x^x at x=1. Also called Lehmer-Comtet numbers}}</ref>
* '''47321'''/33461 ≈ [[square root of 2|√2]]

===48000 to 48999===
* '''48629''' = number of trees with 17 unlabeled nodes<ref>{{cite OEIS|A000055|Number of trees with n unlabeled nodes}}</ref>
* '''48734''' = number of 22-bead necklaces (turning over is allowed) where complements are equivalent<ref>{{cite OEIS|A000011|Number of n-bead necklaces (turning over is allowed) where complements are equivalent}}</ref>

===49000 to 49999===
* '''49151''' = [[Woodall number]]<ref>{{Cite OEIS|A003261|Woodall numbers}}</ref>
* '''49152''' = 3-[[smooth number]]
* '''49726''' = pentagonal pyramidal number
* '''49940''' = number of 21-bead binary necklaces with beads of 2 colors where the colors may be swapped but turning over is not allowed<ref>{{cite OEIS|A000013|Definition (1): Number of n-bead binary necklaces with beads of 2 colors where the colors may be swapped but turning over is not allowed}}</ref>

===Primes===
There are 930 prime numbers between 40000 and 50000.

==References==
{{Reflist}}

{{Integers|10}}

[[Category:Integers|40000]]