Number

218

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

Deficient Number Odious Number Pernicious Number Recamán's Sequence Semiprime Squarefree Year

Historical context — 218 AD

Calendar year

Year 218 (CCXVIII) was a common year starting on Thursday of the Julian calendar.

Excerpt from Wikipedia (en) ↗ · Licensed CC BY-SA 4.0 · English fallback Read the full article on Wikipedia →

Notable events — 218 BC

Undated Hannibal crosses the Alps with his army and elephants, opening the Second Punic War.

Events compiled from Wikipedia ↗ · Licensed CC BY-SA 4.0

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: 53
Long year: contains 53 ISO weeks.
Started on: Thursday
January 1, 218
Ended on: Thursday
December 31, 218
Friday the 13ths: 3
3 Friday the 13ths this year.
Decade: 210s
210–219
Century: 3rd century
201–300
Millennium: 1st millennium
1–1000
Years ago: 1,808
1808 years before 2026.

In other calendars

Hebrew: 3978 / 3979 AM
Rosh Hashanah falls in September/October.
Chinese: Year of the zodiac:Earth zodiac:Dog
Sexagenary cycle position 35 of 60. Lunar new year falls in late January / mid-February.
Buddhist Era: 761 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
Ethiopian: 210 / 211 ET
Year boundary at Enkutatash (September 11/12).
Indian National (Saka): 140 / 139 Saka
Indian national calendar; year starts in March.

Properties

Parity: Even
Digit count: 3
Digit sum: 11
Digit product: 16
Digital root: 2
Palindrome: No
Bit width: 8 bits
Reversed: 812
Recamán's sequence: a(2,596) = 218
Square (n²): 47,524
Cube (n³): 10,360,232
Divisor count: 4
σ(n) — sum of divisors: 330
φ(n) — Euler's totient: 108
Sum of prime factors: 111

Primality

Prime factorization: 2 × 109

Nearest primes: 211 (−7) · 223 (+5)

Divisors & multiples

All divisors (4)

1 · 2 · 109 (half) · 218

Aliquot sum (sum of proper divisors): 112

Factor pairs (a × b = 218)

1 × 218

2 × 109

First multiples

218 · 436 (double) · 654 · 872 · 1,090 · 1,308 · 1,526 · 1,744 · 1,962 · 2,180

Sums & aliquot sequence

As a sum of two squares: 7² + 13²

As consecutive integers: 53 + 54 + 55 + 56

Aliquot sequence: 218 → 112 → 136 → 134 → 70 → 74 → 40 → 50 → 43 → 1 → 0 — terminates at zero

Representations

In words: two hundred eighteen
Ordinal: 218th
Roman numeral: CCXVIII
Binary: 11011010
Octal: 332
Hexadecimal: 0xDA
Base64: 2g==
One's complement: 37 (8-bit)

In other bases

ternary (3) 22002

quaternary (4) 3122

quinary (5) 1333

senary (6) 1002

septenary (7) 431

nonary (9) 262

undecimal (11) 189

duodecimal (12) 162

tridecimal (13) 13a

tetradecimal (14) 118

pentadecimal (15) e8

Historical numeral systems

Babylonian (base 60): 𒁹𒁹𒁹 𒌋𒌋𒌋𒁹𒁹𒁹𒁹𒁹𒁹𒁹𒁹
Egyptian hieroglyphic: 𓍢𓍢𓎆𓏺𓏺𓏺𓏺𓏺𓏺𓏺𓏺
Greek (Milesian): σιηʹ
Mayan (base 20): 𝋪·𝋲
Chinese: 二百一十八
Chinese (financial): 貳佰壹拾捌

In other modern scripts

Eastern Arabic ٢١٨ Devanagari २१८ Bengali ২১৮ Tamil ௨௧௮ Thai ๒๑๘ Tibetan ༢༡༨ Khmer ២១៨ Lao ໒໑໘ Burmese ၂၁၈

Digit at this position in famous constants

π — Pi (π): Digit 218 = 4
e — Euler's number (e): Digit 218 = 1
φ — Golden ratio (φ): Digit 218 = 7
√2 — Pythagoras's (√2): Digit 218 = 2
ln 2 — Natural log of 2: Digit 218 = 1
γ — Euler-Mascheroni (γ): Digit 218 = 6

Also seen as

Goldbach decomposition

Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 218, here are decompositions:

7 + 211 = 218
19 + 199 = 218
37 + 181 = 218
61 + 157 = 218
67 + 151 = 218
79 + 139 = 218
109 + 109 = 218

Unicode codepoint

Latin Capital Letter U With Acute

U+00DA

Uppercase letter (Lu)

UTF-8 encoding: C3 9A (2 bytes).

Lookup U+00DA on Compart ↗ Lookup on FileFormat.Info ↗

Hex color

#0000DA

RGB(0, 0, 218)

IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.0.218.

Address: 0.0.0.218
Class: reserved
IPv4-mapped IPv6: ::ffff:0.0.0.218

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

NANP area code 218

The number 218 is an active NANP area code (North American Numbering Plan).

Primary area: Duluth
Region: Minnesota
Country: United States

Most NANP area codes have multiple overlays in dense regions; the primary area listed is the historic/largest population center for this code.

Look up area code 218 ↗