291
291 is a composite number, odd, a calendar year.
Historical context — 291 AD
Calendar year
Year 291 (CCXCI) was a common year starting on Thursday of the Julian calendar.
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Historical context — 291 BC
Calendar year
Year 291 BC was a year of the pre-Julian Roman 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
-
53
Long year: contains 53 ISO weeks.
- Started on
-
Thursday
January 1, 291
- Ended on
-
Thursday
December 31, 291
- Friday the 13ths
-
3
3 Friday the 13ths this year.
- Decade
-
290s
290–299
- Century
-
3rd century
201–300
- Millennium
-
1st millennium
1–1000
- Years ago
-
1,735
1735 years before 2026.
In other calendars
- Hebrew
-
4051 / 4052 AM
Rosh Hashanah falls in September/October.
- 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
-
834 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
- Ethiopian
-
283 / 284 ET
Year boundary at Enkutatash (September 11/12).
- Indian National (Saka)
-
213 / 212 Saka
Indian national calendar; year starts in March.
Properties
Primality
Prime factorization: 3 × 97
Divisors & multiples
Sums & aliquot sequence
Representations
- In words
- two hundred ninety-one
- Ordinal
- 291st
- Roman numeral
- CCXCI
- Binary
- 100100011
- Octal
- 443
- Hexadecimal
- 0x123
- Base64
- ASM=
- One's complement
- 65,244 (16-bit)
Historical numeral systems
- Babylonian (base 60)
- 𒁹𒁹𒁹𒁹 𒌋𒌋𒌋𒌋𒌋𒁹
- Egyptian hieroglyphic
- 𓍢𓍢𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓏺
- Greek (Milesian)
- σϟαʹ
- Mayan (base 20)
- 𝋮·𝋫
- Chinese
- 二百九十一
- Chinese (financial)
- 貳佰玖拾壹
Digit at this position in famous constants
- π — Pi (π)
- Digit 291 = 6
- e — Euler's number (e)
- Digit 291 = 7
- φ — Golden ratio (φ)
- Digit 291 = 4
- √2 — Pythagoras's (√2)
- Digit 291 = 9
- ln 2 — Natural log of 2
- Digit 291 = 1
- γ — Euler-Mascheroni (γ)
- Digit 291 = 0
Also seen as
UTF-8 encoding: C4 A3 (2 bytes).
As an unsigned 32-bit integer, this is the IPv4 address 0.0.1.35.
- Address
- 0.0.1.35
- Class
- reserved
- IPv4-mapped IPv6
- ::ffff:0.0.1.35
Unspecified address (0.0.0.0/8) — "this network" placeholder.
This passes the ABA routing number checksum and matches the Federal Reserve numbering scheme.
Banks operate many routing numbers per state and division; an unmatched checksum-valid number can still be a real RTN at a smaller institution.