Number

1,266

1,266 is a composite number, even, a calendar year.

1,266 (one thousand two hundred sixty-six) is an even 4-digit number. It is a composite number with 8 divisors, and factors as 2 × 3 × 211. Its proper divisors sum to 1,278, more than the number itself, making it an abundant number. Written other ways, in Roman numerals it is MCCLXVI and in binary, 10011110010.

Abundant Number Arithmetic Number Cube-Free Evil Number Recamán's Sequence Semiperfect Number Sphenic Number Squarefree Year

Interestingness

★ ★ ★ ★ ☆

6 notable facts · grade B

1,254 1,255 1,256 1,257 1,258 1,259 1,260 1,261 1,262 1,263 1,264 1,265 1,266 1,267 1,268 1,269 1,270 1,271 1,272 1,273 1,274 1,275 1,276 1,277 1,278

less more

Historical context — 1266 AD

Calendar year

Year 1266 (MCCLXVI) was a common year starting on Friday of the Julian calendar.

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

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: Friday
January 1, 1266
Ended on: Friday
December 31, 1266
Friday the 13ths: 1
One Friday the 13th this year.
Decade: 1260s
1260–1269
Century: 13th century
1201–1300
Millennium: 2nd millennium
1001–2000
Years ago: 760
760 years before 2026.

In other calendars

Hebrew: 5026 / 5027 AM
Rosh Hashanah falls in September/October.
Islamic Hijri: 664 / 665 AH
Lunar calendar; year spans differ from Gregorian.
Chinese: Year of the zodiac:Fire zodiac:Tiger
Sexagenary cycle position 3 of 60. Lunar new year falls in late January / mid-February.
Buddhist Era: 1809 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
Persian Solar Hijri: 644 / 645 SH
Iranian calendar; Nowruz (new year) falls on the spring equinox.
Ethiopian: 1258 / 1259 ET
Year boundary at Enkutatash (September 11/12).
Indian National (Saka): 1188 / 1187 Saka
Indian national calendar; year starts in March.

Properties

Parity: Even
Digit count: 4
Digit sum: 15
Digit product: 72
Digital root: 6
Palindrome: No
Bit width: 11 bits
Reversed: 6,621
Recamán's sequence: a(8,456) = 1,266
Square (n²): 1,602,756
Cube (n³): 2,029,089,096
Divisor count: 8
σ(n) — sum of divisors: 2,544
φ(n) — Euler's totient: 420
Sum of prime factors: 216

Primality

Prime factorization: 2 × 3 × 211

Nearest primes: 1,259 (−7) · 1,277 (+11)

Divisors & multiples

All divisors (8)

1 · 2 · 3 · 6 · 211 · 422 · 633 (half) · 1266

Aliquot sum (sum of proper divisors): 1,278

Factor pairs (a × b = 1,266)

1 × 1266

2 × 633

3 × 422

6 × 211

First multiples

1,266 · 2,532 (double) · 3,798 · 5,064 · 6,330 · 7,596 · 8,862 · 10,128 · 11,394 · 12,660

Sums & aliquot sequence

As consecutive integers: 421 + 422 + 423 315 + 316 + 317 + 318 100 + 101 + … + 111

Aliquot sequence: 1,266 → 1,278 → 1,530 → 2,682 → 3,168 → 6,660 → 14,088 → 21,192 → 31,848 → 47,832 → 71,808 → 148,512 → 359,520 → 946,848 → 1,895,712 → 4,539,360 → 12,180,336 — unresolved within range

Continued fraction of √n

√1,266 = [35; (1, 1, 2, 1, 1, 2, 3, 1, 3, 1, 34, 1, 3, 1, 3, 2, 1, 1, 2, 1, 1, 70)]

Period length 22 — the block in parentheses repeats forever.

Representations

In words: one thousand two hundred sixty-six
Ordinal: 1266th
Roman numeral: MCCLXVI
Binary: 10011110010
Octal: 2362
Hexadecimal: 0x4F2
Base64: BPI=
One's complement: 64,269 (16-bit)
Scientific notation: 1.266 × 10³
As a duration: 1,266 s = 21 minutes, 6 seconds

In other bases

ternary (3) 1201220

quaternary (4) 103302

quinary (5) 20031

senary (6) 5510

septenary (7) 3456

nonary (9) 1656

undecimal (11) a51

duodecimal (12) 896

tridecimal (13) 765

tetradecimal (14) 666

pentadecimal (15) 596

Palindromic in base 14

As an angle

1,266° = 3 × 360° + 186°

186° ≈ 3.246 rad

Compass bearing: S (south)

Why does a circle have 360 degrees? →

Historical numeral systems

Babylonian (base 60): 𒌋𒌋𒁹 𒁹𒁹𒁹𒁹𒁹𒁹
Egyptian hieroglyphic: 𓆼𓍢𓍢𓎆𓎆𓎆𓎆𓎆𓎆𓏺𓏺𓏺𓏺𓏺𓏺
Greek (Milesian): ͵ασξϛʹ
Mayan (base 20): 𝋣·𝋣·𝋦
Chinese: 一千二百六十六
Chinese (financial): 壹仟貳佰陸拾陸

In other modern scripts

Eastern Arabic ١٢٦٦ Devanagari १२६६ Bengali ১২৬৬ Tamil ௧௨௬௬ Thai ๑๒๖๖ Tibetan ༡༢༦༦ Khmer ១២៦៦ Lao ໑໒໖໖ Burmese ၁၂၆၆

Digit at this position in famous constants

π — Pi (π): Digit 1,266 = 2
e — Euler's number (e): Digit 1,266 = 5
φ — Golden ratio (φ): Digit 1,266 = 4
√2 — Pythagoras's (√2): Digit 1,266 = 9
ln 2 — Natural log of 2: Digit 1,266 = 9
γ — Euler-Mascheroni (γ): Digit 1,266 = 4

Also seen as

Goldbach decomposition

Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 1266, here are decompositions:

7 + 1259 = 1266
17 + 1249 = 1266
29 + 1237 = 1266
37 + 1229 = 1266
43 + 1223 = 1266
53 + 1213 = 1266
73 + 1193 = 1266
79 + 1187 = 1266

Showing the first eight; more decompositions exist.

Unicode codepoint

Cyrillic Capital Letter U With Double Acute

U+04F2

Uppercase letter (Lu)

UTF-8 encoding: D3 B2 (2 bytes).

Lookup U+04F2 on Compart ↗ Lookup on FileFormat.Info ↗

Hex color

#0004F2

RGB(0, 4, 242)

IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.4.242.

Address: 0.0.4.242
Class: reserved
IPv4-mapped IPv6: ::ffff:0.0.4.242

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

Musical pitch

Heard as a frequency, 1,266 Hz is closest to:

Concert pitch (A4 = 440 Hz): D♯6 (1244.5 Hz, +30¢)
Scientific pitch (C4 = 256 Hz): E6 (1290.2 Hz, -33¢)
Baroque pitch (A4 = 415 Hz): E6 (1243.6 Hz, +31¢)

Position in π

The digit sequence 1266 first appears in π at position 4,160 of the decimal expansion (the 4,160ordinal-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.

Look up 1266 on Pi Search ↗