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Zahl

13

13 — Thirteen

13 is a prime, odd, a calendar year.

Thirteen is the sixth prime and is widely considered unlucky in many Western cultures (a phenomenon called triskaidekaphobia). It is also the smallest emirp — a prime whose digit reversal (31) is a different prime.

Quellen https://en.wikipedia.org/wiki/13_(number)
Cousin Prime Curated Deficient Number Fibonacci Happy Number Prime Recamán's Sequence Sexy Prime Squarefree Twin Prime

Eigenschaften

Parität
Ungerade
Stellenanzahl
2
Quersumme
4
Iterierte Quersumme
4
Palindrom
Nein
Umgekehrt
31
Recamán-Folge
a(6) = 13
Anzahl der Teiler
2
σ(n) — Summe der Teiler
14

Primzahleigenschaft

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

Teiler und Vielfache

All divisors (2)
1 · 13
Aliquot sum (sum of proper divisors): 1
Factor pairs (a × b = 13)
1 × 13
First multiples
13 · 26 · 39 · 52 · 65 · 78 · 91 · 104 · 117 · 130

Darstellungen

In Worten
thirteen
Ordinal
13th
Römische Zahl
XIII
Binär
1101
Oktal
15
Hexadezimal
0xD
Base64
DQ==

Auch zu sehen als

Prime neighborhood

Adjacent primes:

  • Previous prime: 11 (gap of 2)
  • Next prime: 17 (gap of 4)

Pair status: twin with 11, cousin with 17.

ASCII character

As an ASCII codepoint, 13 is CR (carriage return). ASCII control character.

Hex color
#00000D
RGB(0, 0, 13)
IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.0.13.

Address
0.0.0.13
Class
reserved
IPv4-mapped IPv6
::ffff:0.0.0.13

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

Possible US bank routing number

This passes the ABA routing number checksum and matches the Federal Reserve numbering scheme.

Routing number
000000013
Federal Reserve
United States Government

Banks operate many routing numbers per state and division; an unmatched checksum-valid number can still be a real RTN at a smaller institution.