20,000

20k the type of foot race 20K run 20000 Armenian Ֆ 20,000 (twenty thousand) is the natural number that comes after 19,999 and before 20,001. Selected numbers in the range 20001–29999 20001 to 20999 20002 = number of surface-points of a tetrahedron with edge-length 100A005893 Number of points on surface of tetrahedron 20067 = former smallest uninteresting number2023-08-08 Reviews https://www.tandfonline.com/doi/full/10.1080/0025570X.2023.2234204 Mathematics Magazine en 96 4 479–480 10.1080/0025570X.2023.2234204 0025-570X subscription Bischoff Manon The Most Boring Number in the World Is ... https://www.scientificamerican.com/article/the-most-boring-number-in-the-world-is/ Scientific American 2026-09-17Sloane N. J. A. Search: 20067 https://oeis.org/search?q=20067&go=Search The On-Line Encyclopedia of Integer Sequences 2026-09-17 20100 = sum of the first 200 natural numbers (hence the 200th triangular number) 20160 = 23rd highly composite number;A002182 Highly composite numbers smallest order belonging to two non-isomorphic simple groups: the alternating group A8 and the Chevalley group A2(4) 20161 = largest integer that cannot be expressed as a sum of two abundant numbers 20230 = pentagonal pyramidal numberA002411 Pentagonal pyramidal numbers 20412 = Leyland number:A076980 Leyland numbers 93 + 39 20540 = square pyramidal numberA000330 Square pyramidal numbers 20569 = tetranacci numberA000078 Tetranacci numbers 20593 = unique prime in base 12 20736 = 1442 = 124, 1000012, palindromic in base 15 (622615), also called a dozen great-gross in some duodecimal nomenclature. 20793 = little Schroeder number 20871 = number of weeks in exactly 400 years in the Gregorian calendar 20903 = first prime of form 120k + 23 that is not a full reptend prime 20990 = current smallest uninteresting number 21000 to 21999 21025 = 1452, palindromic in base 12 (1020112) 21147 = Bell numberA000110 Bell or exponential numbers 21181 = the least of five remaining Seventeen or Bust numbers in the Sierpiński problem 21209 = number of reduced trees with 23 nodesA000014 Number of series-reduced trees with n nodes 21637 = number of partitions of 37A000041 a(n) is the number of partitions of n (the partition numbers) 21856 = octahedral numberA005900 Octahedral numbers 21943 = Friedman prime 22000 to 22999 22050 = pentagonal pyramidal number 22140 = square pyramidal number 22222 = repdigit, Kaprekar number:A006886 Kaprekar numbers 222222 = 493817284, 4938 + 17284 = 22222 22447 = cuban primeA002407 Cuban primes 22527 = Woodall number: 11 × 211 − 1A003261 Woodall numbers 22621 = repunit prime in base 12 22699 = one of five remaining Seventeen or Bust numbers in the Sierpiński problem 23000 to 23999 23000 = number of primes .A007053 Number of primes [greater than or equal to] 2^n 2022-06-02 23401 = Leyland number: 65 + 56 23409 = 1532, sum of the cubes of the first 17 positive integers 23497 = cuban prime 23821 = square pyramidal number 23833 = Padovan prime 23969 = octahedral number 23976 = pentagonal pyramidal number 23982 = year in which the Gregorian calendar will begin to differ from the tropical year by one week.Mansingh Aryan April 26, 2024 Leap Seconds, Cesium Clocks, and How the World is Falling Behind https://sites.imsa.edu/hadron/2024/04/26/leap-seconds-cesium-clocks-and-how-the-world-is-falling-behind/ September 2, 2026 imsa.edu en 24000 to 24999 24000 = number of primitive polynomials of degree 20 over GF(2)A011260 Number of primitive polynomials of degree n over GF(2) 24211 = Zeisel numberA051015 Zeisel numbers 24336 = 1562, palindromic in base 5: 12343215 24389 = 293 24571 = cuban prime 24631 = Wedderburn–Etherington primeA001190 Wedderburn-Etherington numbers 24649 = 1572, palindromic in base 12: 1232112 24737 = one of five remaining Seventeen or Bust numbers in the Sierpinski problem 24742 = number of signed trees with 10 nodesA000060 Number of signed trees with n nodes 25000 to 25999 25011 = the smallest composite number, ending in 1, 3, 7, or 9, that in base 10 remains composite after any insertion of a digit 25085 = Zeisel number 25117 = cuban prime 25200 = 224th triangular number, 24th highly composite number,A002182 - OEIS https://oeis.org/A002182 2024-11-28 oeis.org smallest number with exactly 90 factors 25205 = largest number whose factorial is less than 10100000 25482 = number of 21-bead necklaces (turning over is allowed) where complements are equivalentA000011 Number of n-bead necklaces (turning over is allowed) where complements are equivalent 25585 = square pyramidal number 25724 = Fine numberA000957 Fine's sequence (or Fine numbers): number of relations of valence > 0 on an n-set; also number of ordered rooted trees with n edges having root of even degree 2022-06-01 25920 = smallest number with exactly 70 factors 26000 to 26999 26015 = number of partitions of 38A000041 a(n) is the number of partitions of n (the partition numbers) 26214 = octahedral number 26227 = cuban prime 26272 = number of 20-bead binary necklaces with beads of 2 colors where the colors may be swapped but turning over is not allowedA000013 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 26861 = smallest number for which there are more primes of the form 4k + 1 than of the form 4k + 3 up to the number, against Chebyshev's bias 26896 = 1642, palindromic in base 9: 408049 26955 = amount of SI days in the average human lifetime of 73.8 calendar years.January 2017 Life Expectancy at Birth https://www.un.org/development/desa/pd/sites/www.un.org.development.desa.pd/files/files/documents/2020/Jan/un_2017_techpaper7.pdf September 3, 2026 un.org en 27000 to 27999 27405 = heptagonal number,A000566 Heptagonal numbers hexadecagonal number,A051868 Hexadecagonal numbers 48-gonal number, 80-gonal number, smallest integer that is polygonal in exactly 10 ways.A063778 a(n) = the least integer that is polygonal in exactly n ways. 27434 = square pyramidal number 27559 = Zeisel number 27594 = number of primitive polynomials of degree 19 over GF(2) 27648 = 11 × 22 × 33 × 44 27653 = Friedman prime 27720 = 25th highly composite number; smallest number divisible by the numbers from 1 to 12 (there is no smaller number divisible by the numbers from 1 to 11 since any number divisible by 3 and 4 must be divisible by 12) 27846 = harmonic divisor numberhttps://oeis.org/A001599 Sloane's A001599 : Harmonic or Ore numbers The On-Line Encyclopedia of Integer Sequences OEIS Foundation 2016-06-15 28000 to 28999 28158 = pentagonal pyramidal number 28374 = smallest integer to start a run of six consecutive integers with the same number of divisors 28393 = unique prime in base 13 28547 = Friedman prime 28559 = nice Friedman prime 28561 = 1692 = 134 = 1192 + 1202, number that is simultaneously a square number and a centered square number, palindromic in base 12: 1464112 28595 = octahedral number 28657 = Fibonacci prime,https://oeis.org/A000045 Sloane's A000045 : Fibonacci numbers The On-Line Encyclopedia of Integer Sequences OEIS Foundation 2016-06-15 Markov primehttps://oeis.org/A002559 Sloane's A002559 : Markoff (or Markov) numbers The On-Line Encyclopedia of Integer Sequences OEIS Foundation 2016-06-15 28900 = 1702, palindromic in base 13: 1020113 29000 to 29999 29241 = 1712, sum of the cubes of the first 18 positive integers 29341 = Carmichael numberhttps://oeis.org/A002997 Sloane's A002997 : Carmichael numbers The On-Line Encyclopedia of Integer Sequences OEIS Foundation 2016-06-15 29370 = square pyramidal number 29527 = Friedman prime 29531 = Friedman prime 29601 = number of planar partitions of 18A000219 Number of planar partitions (or plane partitions) of n Primes There are 983 prime numbers between 20000 and 30000. References 10000 20000