20000 (number)

← 19999 20001 → 20000
List of numbers — Integers ← 10k 20k 30k 40k 50k 60k 70k 80k 90k →
Cardinal	20000
Ordinal	20000th (twenty thousandth)
Factorization
Roman numeral	XX
Binary	1001110001000002
Octal	470408
Duodecimal	B6A812
Hexadecimal	4E2016

20,000 (twenty thousand) is the number that comes after 19,999 and before 20,001.

Selected numbers

• 20000 – round number; also in the title of Jules Verne's novel 20,000 Leagues Under The Sea
• 20081 – Motorola 68K instruction for no operation (NOP)
• 20100 – sum of the first 200 natural numbers (hence a triangular number)
• 20160 – the smallest order belonging to two non-isomorphic simple groups: the alternating group A₈ and the Chevalley group A₂(4)
• 20161 – the largest integer that cannot be expressed as a sum of two abundant numbers
• 20230 – pentagonal pyramidal number
• 20412 – Leyland number
• 20540 – square pyramidal number
• 20569 – tetranacci number
• 20903 – first prime of form 120k+23 that is not a full reptend prime
• 21147 – Bell number
• 21181 – one of six remaining Seventeen or Bust numbers in the Sierpinski problem
• 21856 – octahedral number
• 21978 - reverses when multiplied by 4
• 22050 – pentagonal pyramidal number
• 22140 – square pyramidal number
• 22222 – Kaprekar number
• 22447 – cuban prime
• 22527 – Woodall number
• 22699 – one of six remaining Seventeen or Bust numbers in the Sierpinski problem
• 23401 – Leyland number
• 23409 – sum of the cubes of the first 17 positive integers
• 23497 – cuban prime
• 23821 – square pyramidal number
• 23969 – octahedral number
• 23976 – pentagonal pyramidal number
• 24211 – Zeisel number
• 24571 – cuban prime
• 24601 – Jean Valjean's prisoner number in Les Miserables
• 24631 – Wedderburn-Etherington number
• 24737 – one of six remaining Seventeen or Bust numbers in the Sierpinski problem
• 25011 – the first composite number that in base 10 remains composite after any insertion of a digit
• 25085 – Zeisel number
• 25117 – cuban prime
• 25205 – largest number whose factorial is less than 10¹⁰⁰⁰⁰⁰
• 25585 – square pyramidal number
• 26214 – octahedral number
• 26227 – cuban prime
• 26861 – smallest number below which there are more primes of the form 4k + 1 than of the form 4k + 3
• 27434 – square pyramidal number
• 27559 – Zeisel number
• 27648 – 1¹*2²*3³*4⁴
• 27720 – smallest number divisible by the numbers 1 to 12 (there is no smaller number divisible by the numbers 1 to 11)
• 27846 – harmonic divisor number
• 28158 – pentagonal pyramidal number
• 28374 – smallest integer to start a run of six consecutive integers with the same number of divisors
• 28561 – , number that is simultaneously a square number and a centered square number
• 28595 – octahedral number
• 28657 – Fibonacci number, Markov number
• 29241 – sum of the cubes of the first 18 positive integers
• 29341 – Carmichael number
• 29370 – square pyramidal number