531
531 is a composite number, odd, a calendar year.
Historical context — 531 AD
Calendar year
Year 531 (DXXXI) was a common year starting on Wednesday of the Julian calendar.
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Historical context — 531 BC
Calendar year
The year 531 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
- 52
- Started on
-
Monday
January 1, 531
- Ended on
-
Monday
December 31, 531
- Friday the 13ths
-
2
2 Friday the 13ths this year.
- Decade
-
530s
530–539
- Century
-
6th century
501–600
- Millennium
-
1st millennium
1–1000
- Years ago
-
1,495
1495 years before 2026.
In other calendars
- Hebrew
-
4291 / 4292 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
-
1074 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
- Ethiopian
-
523 / 524 ET
Year boundary at Enkutatash (September 11/12).
- Indian National (Saka)
-
453 / 452 Saka
Indian national calendar; year starts in March.
Properties
Primality
Prime factorization: 3 2 × 59
Divisors & multiples
Sums & aliquot sequence
Representations
- In words
- five hundred thirty-one
- Ordinal
- 531st
- Roman numeral
- DXXXI
- Binary
- 1000010011
- Octal
- 1023
- Hexadecimal
- 0x213
- Base64
- AhM=
- One's complement
- 65,004 (16-bit)
Historical numeral systems
- Babylonian (base 60)
- 𒁹𒁹𒁹𒁹𒁹𒁹𒁹𒁹 𒌋𒌋𒌋𒌋𒌋𒁹
- Egyptian hieroglyphic
- 𓍢𓍢𓍢𓍢𓍢𓎆𓎆𓎆𓏺
- Greek (Milesian)
- φλαʹ
- Mayan (base 20)
- 𝋡·𝋦·𝋫
- Chinese
- 五百三十一
- Chinese (financial)
- 伍佰參拾壹
Digit at this position in famous constants
- π — Pi (π)
- Digit 531 = 4
- e — Euler's number (e)
- Digit 531 = 0
- φ — Golden ratio (φ)
- Digit 531 = 3
- √2 — Pythagoras's (√2)
- Digit 531 = 2
- ln 2 — Natural log of 2
- Digit 531 = 2
- γ — Euler-Mascheroni (γ)
- Digit 531 = 5
Also seen as
UTF-8 encoding: C8 93 (2 bytes).
As an unsigned 32-bit integer, this is the IPv4 address 0.0.2.19.
- Address
- 0.0.2.19
- Class
- reserved
- IPv4-mapped IPv6
- ::ffff:0.0.2.19
Unspecified address (0.0.0.0/8) — "this network" placeholder.
The number 531 is an active NANP area code (North American Numbering Plan).
- Primary area
- Omaha
- Region
- Nebraska
- Country
- United States
Most NANP area codes have multiple overlays in dense regions; the primary area listed is the historic/largest population center for this code.