The quadryllion is equal to \(10^{64}\) in the myriad system[1][2], or 10 squared 6 times.

It is also called fukashigi (不可思議 written in Japanese characters, means "inconceivable").[3][4] The word is in Buddhism's sutra, and it was adopted in Chinese counting system and in Japanese counting system.

Decimal expansion



Notation Lower bound Upper bound
Scientific notation \(1\times10^{64}\)
Arrow notation \(10\uparrow64\)
Steinhaus-Moser Notation 39[3] 40[3]
Copy notation 9[64] 1[65]
Taro's multivariable Ackermann function A(3,209) A(3,210)
Pound-Star Notation #*(4,2,8,0,1,3)*7 #*(5,2,8,0,1,3)*7
BEAF {10,64}
Hyper-E notation E64
Bashicu matrix system (0)(0)(0)(0)[10000]
Hyperfactorial array notation 49! 50!
Fast-growing hierarchy \(f_2(204)\) \(f_2(205)\)
Hardy hierarchy \(H_{\omega^2}(204)\) \(H_{\omega^2}(205)\)
Slow-growing hierarchy \(g_{\omega^{\omega6+4}}(10)\)


  1. Myriad system on Wikipedia
  2. Large numbers By Robert Munafo
  3. Book of Numbers by J.H. Conway and R.K. Guy
  4. 大数の名前

See also

myllion byllion tryllion quadryllion quintyllion
sextyllion septyllion octyllion nonyllion decyllion
undecyllion duodecyllion tredecyllion quattuordecyllion quindecyllion
sexdecyllion septdecyllion octodecyllion novemdecyllion vigintyllion
unvigintyllion duovigintyllion trevigintyllion quattuorvigintyllion quinvigintyllion
sexvigintyllion septemvigintyllion octovigintyllion novemvigintyllion trigintyllion
untrigintyllion duotrigintyllion tretrigintyllion quattuortrigintyllion quintrigintyllion
sextrigintyllion septtrigintyllion octotrigintyllion novemtrigintyllion quadragintyllion
quinquagintyllion sexagintyllion septuagintyllion octogintyllion nonagintyllion
centyllion ducentyllion trecentyllion quadringentyllion quingentyllion
sescentyllion septingentyllion octingentyllion nongentyllion millyllion
myryllion micryllion nanyllion picyllion femtyllion
attyllion zeptyllion yoctyllion googolyllion latinlatinlatinbyllionyllionyllionyllion
Googology in Asia

Fish numbers: Fish number 1 · Fish number 2 · Fish number 3 · Fish number 4 · Fish number 5 · Fish number 6 · Fish number 7
Mapping functions: S map · SS map · S(n) map · M(n) map · M(m,n) map
By Aeton: Okojo numbers · N-growing hierarchy
By BashicuHyudora: Primitive sequence number · Pair sequence number · Bashicu matrix system
By Jason: Irrational arrow notation · δOCF · δφ
By mrna: SSAN · S-σ
By Nayuta Ito: N primitive
By Yukito: Hyper primitive sequence system · Y sequence · Y function
Indian counting system: Lakh · Crore · Uppala
Chinese, Japanese and Korean counting system: Wan · Yi · Zhao · Jing · Gai · Zi · Rang · Gou · Jian · Zheng · Zai · Ji · Gougasha · Asougi · Nayuta · Fukashigi · Muryoutaisuu
Buddhist text: Tallakshana · Dvajagravati · Mahakathana · Asankhyeya · Dvajagranisamani · Vahanaprajnapti · Inga · Kuruta · Sarvanikshepa · Agrasara · Uttaraparamanurajahpravesa · Avatamsaka Sutra · Nirabhilapya nirabhilapya parivarta
Other: Taro's multivariable Ackermann function · Sushi Kokuu Hen

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