1,191
1,191 is a composite number, odd, a calendar year.
Historical context — 1191 AD
Calendar year
Year 1191 (MCXCI) was a common year starting on Tuesday 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
-
Tuesday
January 1, 1191
- Ended on
-
Tuesday
December 31, 1191
- Friday the 13ths
-
2
2 Friday the 13ths this year.
- Decade
-
1190s
1190–1199
- Century
-
12th century
1101–1200
- Millennium
-
2nd millennium
1001–2000
- Years ago
-
835
835 years before 2026.
In other calendars
- Hebrew
-
4951 / 4952 AM
Rosh Hashanah falls in September/October.
- Islamic Hijri
-
586 / 587 AH
Lunar calendar; year spans differ from Gregorian.
- Chinese
-
Year of the zodiac:Metal zodiac:Pig
Sexagenary cycle position 48 of 60. Lunar new year falls in late January / mid-February.
- Buddhist Era
-
1734 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
- Persian Solar Hijri
-
569 / 570 SH
Iranian calendar; Nowruz (new year) falls on the spring equinox.
- Ethiopian
-
1183 / 1184 ET
Year boundary at Enkutatash (September 11/12).
- Indian National (Saka)
-
1113 / 1112 Saka
Indian national calendar; year starts in March.
Properties
- Parity
- Odd
- Digit count
- 4
- Digit sum
- 12
- Digit product
- 9
- Digital root
- 3
- Palindrome
- No
- Bit width
- 11 bits
- Reversed
- 1,911
- Flips to (rotate 180°)
- 1,611
- Recamán's sequence
- a(8,606) = 1,191
- Square (n²)
- 1,418,481
- Cube (n³)
- 1,689,410,871
- Divisor count
- 4
- σ(n) — sum of divisors
- 1,592
- φ(n) — Euler's totient
- 792
- Sum of prime factors
- 400
Primality
Prime factorization: 3 × 397
Divisors & multiples
Sums & aliquot sequence
Representations
- In words
- one thousand one hundred ninety-one
- Ordinal
- 1191st
- Roman numeral
- MCXCI
- Binary
- 10010100111
- Octal
- 2247
- Hexadecimal
- 0x4A7
- Base64
- BKc=
- One's complement
- 64,344 (16-bit)
Historical numeral systems
- Babylonian (base 60)
- 𒌋𒁹𒁹𒁹𒁹𒁹𒁹𒁹𒁹𒁹 𒌋𒌋𒌋𒌋𒌋𒁹
- Egyptian hieroglyphic
- 𓆼𓍢𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓏺
- Greek (Milesian)
- ͵αρϟαʹ
- Mayan (base 20)
- 𝋢·𝋳·𝋫
- Chinese
- 一千一百九十一
- Chinese (financial)
- 壹仟壹佰玖拾壹
Digit at this position in famous constants
- π — Pi (π)
- Digit 1,191 = 0
- e — Euler's number (e)
- Digit 1,191 = 8
- φ — Golden ratio (φ)
- Digit 1,191 = 4
- √2 — Pythagoras's (√2)
- Digit 1,191 = 2
- ln 2 — Natural log of 2
- Digit 1,191 = 5
- γ — Euler-Mascheroni (γ)
- Digit 1,191 = 1
Also seen as
UTF-8 encoding: D2 A7 (2 bytes).
As an unsigned 32-bit integer, this is the IPv4 address 0.0.4.167.
- Address
- 0.0.4.167
- Class
- reserved
- IPv4-mapped IPv6
- ::ffff:0.0.4.167
Unspecified address (0.0.0.0/8) — "this network" placeholder.
The digit sequence 1191 first appears in π at position 8,845 of the decimal expansion (the 8,845ordinal-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.