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Number

1,218

1,218 is a composite number, even, a calendar year.

Abundant Number Arithmetic Number Evil Number Happy Number Practical Number Recamán's Sequence Semiperfect Number Squarefree Year

Historical context — 1218 AD

Calendar year

Year 1218 (MCCXVIII) was a common year starting on Monday of the 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
Monday
January 1, 1218
Ended on
Monday
December 31, 1218
Friday the 13ths
2
2 Friday the 13ths this year.
Decade
1210s
1210–1219
Century
13th century
1201–1300
Millennium
2nd millennium
1001–2000
Years ago
808
808 years before 2026.

In other calendars

Hebrew
4978 / 4979 AM
Rosh Hashanah falls in September/October.
Islamic Hijri
614 / 615 AH
Lunar calendar; year spans differ from Gregorian.
Chinese
Year of the zodiac:Earth zodiac:Tiger
Sexagenary cycle position 15 of 60. Lunar new year falls in late January / mid-February.
Buddhist Era
1761 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
Persian Solar Hijri
596 / 597 SH
Iranian calendar; Nowruz (new year) falls on the spring equinox.
Ethiopian
1210 / 1211 ET
Year boundary at Enkutatash (September 11/12).
Indian National (Saka)
1140 / 1139 Saka
Indian national calendar; year starts in March.

Properties

Parity
Even
Digit count
4
Digit sum
12
Digit product
16
Digital root
3
Palindrome
No
Bit width
11 bits
Reversed
8,121
Recamán's sequence
a(8,552) = 1,218
Square (n²)
1,483,524
Cube (n³)
1,806,932,232
Divisor count
16
σ(n) — sum of divisors
2,880
φ(n) — Euler's totient
336
Sum of prime factors
41

Primality

Prime factorization: 2 × 3 × 7 × 29

Nearest primes: 1,217 (−1) · 1,223 (+5)

Divisors & multiples

All divisors (16)
1 · 2 · 3 · 6 · 7 · 14 · 21 · 29 · 42 · 58 · 87 · 174 · 203 · 406 · 609 (half) · 1218
Aliquot sum (sum of proper divisors): 1,662
Factor pairs (a × b = 1,218)
1 × 1218
2 × 609
3 × 406
6 × 203
7 × 174
14 × 87
21 × 58
29 × 42
First multiples
1,218 · 2,436 (double) · 3,654 · 4,872 · 6,090 · 7,308 · 8,526 · 9,744 · 10,962 · 12,180

Sums & aliquot sequence

As consecutive integers: 405 + 406 + 407 303 + 304 + 305 + 306 171 + 172 + … + 177 96 + 97 + … + 107
Aliquot sequence: 1,218 1,662 1,674 2,166 2,406 2,418 2,958 3,522 3,534 4,146 4,158 7,362 8,628 11,532 16,272 29,670 46,362 — unresolved within range

Representations

In words
one thousand two hundred eighteen
Ordinal
1218th
Roman numeral
MCCXVIII
Binary
10011000010
Octal
2302
Hexadecimal
0x4C2
Base64
BMI=
One's complement
64,317 (16-bit)
In other bases
ternary (3) 1200010
quaternary (4) 103002
quinary (5) 14333
senary (6) 5350
septenary (7) 3360
nonary (9) 1603
undecimal (11) a08
duodecimal (12) 856
tridecimal (13) 729
tetradecimal (14) 630
pentadecimal (15) 563

Historical numeral systems

Babylonian (base 60)
𒌋𒌋 𒌋𒁹𒁹𒁹𒁹𒁹𒁹𒁹𒁹
Egyptian hieroglyphic
𓆼𓍢𓍢𓎆𓏺𓏺𓏺𓏺𓏺𓏺𓏺𓏺
Greek (Milesian)
͵ασιηʹ
Mayan (base 20)
𝋣·𝋠·𝋲
Chinese
一千二百一十八
Chinese (financial)
壹仟貳佰壹拾捌
In other modern scripts
Eastern Arabic ١٢١٨ Devanagari १२१८ Bengali ১২১৮ Tamil ௧௨௧௮ Thai ๑๒๑๘ Tibetan ༡༢༡༨ Khmer ១២១៨ Lao ໑໒໑໘ Burmese ၁၂၁၈

Digit at this position in famous constants

π — Pi (π)
Digit 1,218 = 6
e — Euler's number (e)
Digit 1,218 = 3
φ — Golden ratio (φ)
Digit 1,218 = 4
√2 — Pythagoras's (√2)
Digit 1,218 = 5
ln 2 — Natural log of 2
Digit 1,218 = 2
γ — Euler-Mascheroni (γ)
Digit 1,218 = 5

Also seen as

Goldbach decomposition

Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 1218, here are decompositions:

  • 5 + 1213 = 1218
  • 17 + 1201 = 1218
  • 31 + 1187 = 1218
  • 37 + 1181 = 1218
  • 47 + 1171 = 1218
  • 67 + 1151 = 1218
  • 89 + 1129 = 1218
  • 101 + 1117 = 1218

Showing the first eight; more decompositions exist.

Unicode codepoint
ӂ
Cyrillic Small Letter Zhe With Breve
U+04C2
Lowercase letter (Ll)

UTF-8 encoding: D3 82 (2 bytes).

Hex color
#0004C2
RGB(0, 4, 194)
IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.4.194.

Address
0.0.4.194
Class
reserved
IPv4-mapped IPv6
::ffff:0.0.4.194

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

Position in π

The digit sequence 1218 first appears in π at position 9,166 of the decimal expansion (the 9,166ordinal-suffix:th digit after the integer 3).

Search range: the first 1,000,000 fractional digits of π. Any 6-digit-or-shorter string is virtually guaranteed to appear in there — the more interesting signal is the position.