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Number

1,161

1,161 is a composite number, odd, a calendar year.

Arithmetic Number Deficient Number Evil Number Flippable Harshad / Niven Recamán's Sequence Year

Historical context — 1161 AD

Calendar year

Year 1161 (MCLXI) was a common year starting on Sunday 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
Sunday
January 1, 1161
Ended on
Sunday
December 31, 1161
Friday the 13ths
2
2 Friday the 13ths this year.
Decade
1160s
1160–1169
Century
12th century
1101–1200
Millennium
2nd millennium
1001–2000
Years ago
865
865 years before 2026.

In other calendars

Hebrew
4921 / 4922 AM
Rosh Hashanah falls in September/October.
Islamic Hijri
555 / 557 AH
Lunar calendar; year spans differ from Gregorian.
Chinese
Year of the zodiac:Metal zodiac:Snake
Sexagenary cycle position 18 of 60. Lunar new year falls in late January / mid-February.
Buddhist Era
1704 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
Persian Solar Hijri
539 / 540 SH
Iranian calendar; Nowruz (new year) falls on the spring equinox.
Ethiopian
1153 / 1154 ET
Year boundary at Enkutatash (September 11/12).
Indian National (Saka)
1083 / 1082 Saka
Indian national calendar; year starts in March.

Properties

Parity
Odd
Digit count
4
Digit sum
9
Digit product
6
Digital root
9
Palindrome
No
Bit width
11 bits
Reversed
1,611
Flips to (rotate 180°)
1,911
Recamán's sequence
a(1,850) = 1,161
Square (n²)
1,347,921
Cube (n³)
1,564,936,281
Divisor count
8
σ(n) — sum of divisors
1,760
φ(n) — Euler's totient
756
Sum of prime factors
52

Primality

Prime factorization: 3 3 × 43

Nearest primes: 1,153 (−8) · 1,163 (+2)

Divisors & multiples

All divisors (8)
1 · 3 · 9 · 27 · 43 · 129 · 387 · 1161
Aliquot sum (sum of proper divisors): 599
Factor pairs (a × b = 1,161)
1 × 1161
3 × 387
9 × 129
27 × 43
First multiples
1,161 · 2,322 (double) · 3,483 · 4,644 · 5,805 · 6,966 · 8,127 · 9,288 · 10,449 · 11,610

Sums & aliquot sequence

As consecutive integers: 580 + 581 386 + 387 + 388 191 + 192 + 193 + 194 + 195 + 196 125 + 126 + … + 133
Aliquot sequence: 1,161 599 1 0 — terminates at zero

Representations

In words
one thousand one hundred sixty-one
Ordinal
1161st
Roman numeral
MCLXI
Binary
10010001001
Octal
2211
Hexadecimal
0x489
Base64
BIk=
One's complement
64,374 (16-bit)
In other bases
ternary (3) 1121000
quaternary (4) 102021
quinary (5) 14121
senary (6) 5213
septenary (7) 3246
nonary (9) 1530
undecimal (11) 966
duodecimal (12) 809
tridecimal (13) 6b4
tetradecimal (14) 5cd
pentadecimal (15) 526

Historical numeral systems

Babylonian (base 60)
𒌋𒁹𒁹𒁹𒁹𒁹𒁹𒁹𒁹𒁹 𒌋𒌋𒁹
Egyptian hieroglyphic
𓆼𓍢𓎆𓎆𓎆𓎆𓎆𓎆𓏺
Greek (Milesian)
͵αρξαʹ
Mayan (base 20)
𝋢·𝋲·𝋡
Chinese
一千一百六十一
Chinese (financial)
壹仟壹佰陸拾壹
In other modern scripts
Eastern Arabic ١١٦١ Devanagari ११६१ Bengali ১১৬১ Tamil ௧௧௬௧ Thai ๑๑๖๑ Tibetan ༡༡༦༡ Khmer ១១៦១ Lao ໑໑໖໑ Burmese ၁၁၆၁

Digit at this position in famous constants

π — Pi (π)
Digit 1,161 = 6
e — Euler's number (e)
Digit 1,161 = 9
φ — Golden ratio (φ)
Digit 1,161 = 8
√2 — Pythagoras's (√2)
Digit 1,161 = 1
ln 2 — Natural log of 2
Digit 1,161 = 0
γ — Euler-Mascheroni (γ)
Digit 1,161 = 7

Also seen as

Unicode codepoint
҉
Combining Cyrillic Millions Sign
U+0489
Enclosing mark (Me)

UTF-8 encoding: D2 89 (2 bytes).

Hex color
#000489
RGB(0, 4, 137)
IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.4.137.

Address
0.0.4.137
Class
reserved
IPv4-mapped IPv6
::ffff:0.0.4.137

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

Position in π

The digit sequence 1161 first appears in π at position 7,763 of the decimal expansion (the 7,763ordinal-suffix:rd 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.