40000

40000 is the number following 39999 and preceding 40001.

Properties

Its factors are 1, 2, 4, 5, 8, 10, 16, 20, 25, 32, 40, 50, 64, 80, 100, 125, 160, 200, 250, 320, 400, 500, 625, 800, 1000, 1250, 1600, 2000, 2500, 4000, 5000, 8000, 10000, 20000 and 40000, making it a composite number.^[1]^[2]^[3]
40000 is an even number^[4]^[5] .
40000 is an unhappy number.^[6]^[7]

40000 is a centered octagonal number.^[8]
40000 is abundant.^[9]
Its prime factorization is 2⁶ × 5⁴.
40000 is a Harshad number, meaning it is divisible by the sum of its digits.^[10]
The prize for correctly answering the first seven questions in the Indian game show Kaun Banega Crorepati is equal to 40,000 Indian rupees.
It is also used as an approximation for the circumference of the Earth, which is slightly larger than 40,000 km.
In the Hawaiian language, 40,000 is called “kini”.

Notation	Lower bound	Upper bound
Up-arrow notation	200 ↑ 2
Scientific notation	4 x 10⁴	4.001 x 10⁴
Slow-growing hierarchy	\(g_{\omega^{\omega}}(5)\)	\(g_{\omega^{\omega}}(6)\)
Copy notation	3[5]	4[5]
Chained arrow notation	200 → 2
Bowers' Exploding Array Function/Bird's array notation	{200,2}
Fast-growing hierarchy	f₂(11)	f₂(12)
Hardy hierarchy	H_ω(20000)	H_ω(20000)
Middle-growing hierarchy	m(ω,15)	m(ω,16)
Hyper-E notation	E4.6021
Hyper-E notation (non-10 base)	\(E[200]2\)
Hyperfactorial array notation	7!	8!
X-Sequence Hyper-Exponential Notation	200{1}2
Steinhaus-Moser Notation	5[3]	6[3]
PlantStar's Debut Notation	[2]	[3]
H* function	H(0.5)	H(0.6)
Bashicu matrix system with respect to version 4	(0)[200]	(0)[200]
m(n) map	m(1)(5)	m(1)(6)
s(n) map	\(s(1)(\lambda x . x+1)(19999)\)	\(s(1)(\lambda x . x+1)(20000)\)