Nombre

1 729

1729 — The Hardy-Ramanujan Number

1 729 is a composite number, odd, a calendar year.

1729 is the famous taxicab number, the smallest number expressible as the sum of two positive cubes in two different ways:

\(1729 = 1^3 + 12^3 = 9^3 + 10^3\)

The story comes from G. H. Hardy visiting the ailing Ramanujan in hospital. Hardy remarked that he had arrived in cab number 1729, which seemed rather a dull number. Ramanujan immediately replied that, on the contrary, it was a very interesting number — the smallest expressible as the sum of two cubes in two different ways.

Sources https://en.wikipedia.org/wiki/1729_(number)

Carmichael Number Curated Deficient Number Harshad / Niven Recamán's Sequence Sphenic Number Squarefree

Propriétés

Parité: Impair
Nombre de chiffres: 4
Somme des chiffres: 19
Racine numérique: 1
Palindrome: Non
Inversé: 9 271
Suite de Recamán: a(1 198) = 1 729
Nombre de diviseurs: 8
σ(n) — somme des diviseurs: 2 240

Primalité

Prime factorization: 7 × 13 × 19

Diviseurs et multiples

All divisors (8)

1 · 7 · 13 · 19 · 91 · 133 · 247 · 1729

Aliquot sum (sum of proper divisors): 511

Factor pairs (a × b = 1 729)

1 × 1729

7 × 247

13 × 133

19 × 91

First multiples

1 729 · 3 458 · 5 187 · 6 916 · 8 645 · 10 374 · 12 103 · 13 832 · 15 561 · 17 290

Représentations

En lettres: one thousand seven hundred twenty-nine
Ordinal: 1729th
Chiffre romain: MDCCXXIX
Binaire: 11011000001
Octal: 3301
Hexadécimal: 0x6C1
Base64: BsE=

Aussi vu comme

Unicode codepoint

Arabic Letter Heh Goal

U+06C1

Other letter (Lo)

UTF-8 encoding: DB 81 (2 bytes).

Lookup U+06C1 on Compart ↗ Lookup on FileFormat.Info ↗

Hex color

#0006C1

RGB(0, 6, 193)

IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.6.193.

Address: 0.0.6.193
Class: reserved
IPv4-mapped IPv6: ::ffff:0.0.6.193

Unspecified address (0.0.0.0/8) — "this network" placeholder.