Nombre

23

23 — Twenty-Three

23 is a prime, odd, a calendar year.

Twenty-three is the ninth prime, the smallest odd prime that is not a twin prime, and the answer to the birthday problem: in a group of 23 people there is roughly a 50% chance two share a birthday.

Sources https://en.wikipedia.org/wiki/23_(number)

Cousin Prime Curated Deficient Number Happy Number Prime Recamán's Sequence Sexy Prime Squarefree

Propriétés

Parité: Impair
Nombre de chiffres: 2
Somme des chiffres: 5
Racine numérique: 5
Palindrome: Non
Inversé: 32
Suite de Recamán: a(13) = 23
Nombre de diviseurs: 2
σ(n) — somme des diviseurs: 24

Primalité

23 is prime. It has exactly two divisors: 1 and itself.

Diviseurs et multiples

All divisors (2)

1 · 23

Aliquot sum (sum of proper divisors): 1

Factor pairs (a × b = 23)

1 × 23

First multiples

23 · 46 · 69 · 92 · 115 · 138 · 161 · 184 · 207 · 230

Représentations

En lettres: twenty-three
Ordinal: 23rd
Chiffre romain: XXIII
Binaire: 10111
Octal: 27
Hexadécimal: 0x17
Base64: Fw==

Aussi vu comme

Prime neighborhood

Adjacent primes:

Previous prime: 19 (gap of 4)
Next prime: 29 (gap of 6)

Pair status: cousin with 19, sexy with 29.

ASCII character

As an ASCII codepoint, 23 is control character (0x17). ASCII control character.

Network port

TCP/UDP port 23 is the well-known port for Telnet — Plaintext remote login (deprecated).

Hex color

#000017

RGB(0, 0, 23)

IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.0.23.

Address: 0.0.0.23
Class: reserved
IPv4-mapped IPv6: ::ffff:0.0.0.23

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