Number

22

22 is a composite number, even, a calendar year.

Arithmetic Number Deficient Number Odious Number Palindrome Pentagonal Pernicious Number Perrin Number Recamán's Sequence Repdigit Semiprime Smith Number Squarefree Year

Historical context — 22 AD

Calendar year

AD 22 (XXII) was a common year starting on Thursday of the Julian calendar.

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Historical context — 22 BC

Calendar year

Year 22 BC was either a common year starting on Sunday, Monday or Tuesday or a leap year starting on Sunday or Saturday of the Julian calendar and a common year starting on Saturday of the Proleptic Julian calendar.

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Year facts

Year type: Common year
Standard 365-day year; not divisible by 4 (or divisible by 100 but not 400).
Days in year: 365
ISO weeks: 52
Started on: Saturday
January 1, 22
Ended on: Saturday
December 31, 22
Friday the 13ths: 1
One Friday the 13th this year.
Decade: 20s
20–29
Century: 1st century
1–100
Millennium: 1st millennium
1–1000
Years ago: 2,004
2004 years before 2026.

In other calendars

Hebrew: 3782 / 3783 AM
Rosh Hashanah falls in September/October.
Chinese: Year of the zodiac:Water zodiac:Horse
Sexagenary cycle position 19 of 60. Lunar new year falls in late January / mid-February.
Buddhist Era: 565 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
Ethiopian: 14 / 15 ET
Year boundary at Enkutatash (September 11/12).
Indian National (Saka): -56 / -57 Saka
Indian national calendar; year starts in March.

Properties

Parity: Even
Digit count: 2
Digit sum: 4
Digit product: 4
Digital root: 4
Palindrome: Yes
Bit width: 5 bits
Recamán's sequence: a(11) = 22
Square (n²): 484
Cube (n³): 10,648
Divisor count: 4
σ(n) — sum of divisors: 36
φ(n) — Euler's totient: 10
Sum of prime factors: 13

Primality

Prime factorization: 2 × 11

Nearest primes: 19 (−3) · 23 (+1)

Divisors & multiples

All divisors (4)

1 · 2 · 11 (half) · 22

Aliquot sum (sum of proper divisors): 14

Factor pairs (a × b = 22)

1 × 22

2 × 11

First multiples

22 · 44 (double) · 66 · 88 · 110 · 132 · 154 · 176 · 198 · 220

Sums & aliquot sequence

As consecutive integers: 4 + 5 + 6 + 7

Aliquot sequence: 22 → 14 → 10 → 8 → 7 → 1 → 0 — terminates at zero

Representations

In words: twenty-two
Ordinal: 22nd
Roman numeral: XXII
Binary: 10110
Octal: 26
Hexadecimal: 0x16
Base64: Fg==
One's complement: 233 (8-bit)

In other bases

ternary (3) 211

quaternary (4) 112

quinary (5) 42

senary (6) 34

septenary (7) 31

nonary (9) 24

undecimal (11) 20

duodecimal (12) 1a

tridecimal (13) 19

tetradecimal (14) 18

pentadecimal (15) 17

Historical numeral systems

Babylonian (base 60): 𒌋𒌋𒁹𒁹
Egyptian hieroglyphic: 𓎆𓎆𓏺𓏺
Greek (Milesian): κβʹ
Mayan (base 20): 𝋡·𝋢
Chinese: 二十二
Chinese (financial): 貳拾貳

In other modern scripts

Eastern Arabic ٢٢ Devanagari २२ Bengali ২২ Tamil ௨௨ Thai ๒๒ Tibetan ༢༢ Khmer ២២ Lao ໒໒ Burmese ၂၂

Digit at this position in famous constants

π — Pi (π): Digit 22 = 2
e — Euler's number (e): Digit 22 = 0
φ — Golden ratio (φ): Digit 22 = 4
√2 — Pythagoras's (√2): Digit 22 = 1
ln 2 — Natural log of 2: Digit 22 = 7
γ — Euler-Mascheroni (γ): Digit 22 = 6

Also seen as

Goldbach decomposition

Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 22, here are decompositions:

3 + 19 = 22
5 + 17 = 22
11 + 11 = 22

ASCII character

As an ASCII codepoint, 22 is control character (0x16). ASCII control character.

Network port

TCP/UDP port 22 is the well-known port for SSH — Secure Shell — encrypted remote login.

Hex color

#000016

RGB(0, 0, 22)

IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.0.22.

Address: 0.0.0.22
Class: reserved
IPv4-mapped IPv6: ::ffff:0.0.0.22

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