80,000 (eighty thousand) is the
natural number
In mathematics, the natural numbers are the numbers 0, 1, 2, 3, and so on, possibly excluding 0. Some start counting with 0, defining the natural numbers as the non-negative integers , while others start with 1, defining them as the positive in ...
after
79,999 and before 80,001.
Selected numbers in the range 80,000–89,999
* 80,782 =
Pell number
In mathematics, the Pell numbers are an infinite sequence of integers, known since ancient times, that comprise the denominators of the closest rational approximations to the square root of 2. This sequence of approximations begins , , , , an ...
''P''
14
* 81,081 = smallest
abundant number
In number theory, an abundant number or excessive number is a positive integer for which the sum of its proper divisors is greater than the number. The integer 12 is the first abundant number. Its proper divisors are 1, 2, 3, 4 and 6 for a total ...
ending in 1, 3, 7, or 9
* 81,181 = number of reduced trees with 25 nodes
* 82,000 = the only currently known number greater than 1 that can be written in bases from 2 through 5 using only 0s and 1s.
* 82,025 = number of primes
.
* 82,467 = number of square (0,1)-matrices without zero rows and with exactly 6 entries equal to 1
* 82,656 =
Kaprekar number
In mathematics, a natural number in a given number base is a p-Kaprekar number if the representation of its square in that base can be split into two parts, where the second part has p digits, that add up to the original number. For example, in ...
: 82656
2 = 6832014336; 68320 + 14336 = 82656
* 82,944 = 3-
smooth number
In number theory, an ''n''-smooth (or ''n''-friable) number is an integer whose prime factors are all less than or equal to ''n''. For example, a 7-smooth number is a number in which every prime factor is at most 7. Therefore, 49 = 72 and 15750 = 2 ...
: 2
10 × 3
4
* 83,097 =
Riordan number
* 83,160 = the 29th
highly composite number
A highly composite number is a positive integer that has more divisors than all smaller positive integers. If ''d''(''n'') denotes the number of divisors of a positive integer ''n'', then a positive integer ''N'' is highly composite if ''d''(' ...
* 83,357 =
Friedman prime
* 83,521 = 17
4
* 84,187 – number of parallelogram polyominoes with 15 cells.
* 84,375 = 3
3×5
5
* 84,672 = number of primitive polynomials of degree 21 over GF(2)
* 85,085 = product of five consecutive primes: 5 × 7 × 11 × 13 × 17
* 85,184 = 44
3
* 86,400 =
second
The second (symbol: s) is a unit of time derived from the division of the day first into 24 hours, then to 60 minutes, and finally to 60 seconds each (24 × 60 × 60 = 86400). The current and formal definition in the International System of U ...
s in a
day
A day is the time rotation period, period of a full Earth's rotation, rotation of the Earth with respect to the Sun. On average, this is 24 hours (86,400 seconds). As a day passes at a given location it experiences morning, afternoon, evening, ...
: 24 × 60 × 60 and common DNS default
time to live
Time to live (TTL) or hop limit is a mechanism which limits the lifespan or lifetime of data in a computer or network. TTL may be implemented as a counter (digital), counter or timestamp attached to or embedded in the data. Once the prescribed ev ...
* 87,360 =
unitary perfect number
A unitary perfect number is an integer which is the sum of its positive proper unitary divisors, not including the number itself. (A divisor ''d'' of a number ''n'' is a unitary divisor if ''d'' and ''n''/''d'' share no common factors). The numb ...
* 88,789 = the start of a
prime 9-tuple, along with 88793, 88799, 88801, 88807, 88811, 88813, 88817, and 88819.
* 88,888 =
repdigit
In recreational mathematics, a repdigit or sometimes monodigit is a natural number composed of repeated instances of the same digit in a positional number system (often implicitly decimal). The word is a portmanteau of "repeated" and "digit".
Ex ...
* 89,134 = number of partitions of 45
Primes
There are 876 prime numbers between 80000 and 90000.
See also
*
80,000 Hours
80,000 Hours is a London-based nonprofit organisation that conducts research on which careers have the largest positive social impact and provides career advice based on that research. The organisation's name refers to the typical amount of tim ...
, a British social impact career advisory organization
References
{{Integers, 10
80000