1,531
1,531 is a prime, odd, a calendar year.
1,531 (one thousand five hundred thirty-one) is an odd 4-digit number. It is a prime number — divisible only by 1 and itself. Written other ways, in Roman numerals it is MDXXXI and in binary, 10111111011.
Interestingness
Notable events — 1531 AD
- Feb 11 Henry VIII is recognized as Supreme Head of the Church of England.
- Aug 25 A meteor falls near Crema, Italy, signaling "the wrath of God".
- Undated Halley's Comet appears, later identified retrospectively.
Events compiled from Wikipedia ↗ · Licensed CC BY-SA 4.0
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, 1531
- Ended on
-
Thursday
December 31, 1531
- Friday the 13ths
-
3
3 Friday the 13ths this year.
- Decade
-
1530s
1530–1539
- Century
-
16th century
1501–1600
- Millennium
-
2nd millennium
1001–2000
- Years ago
-
495
495 years before 2026.
In other calendars
- Hebrew
-
5291 / 5292 AM
Rosh Hashanah falls in September/October.
- Islamic Hijri
-
937 / 938 AH
Lunar calendar; year spans differ from Gregorian.
- Chinese
-
Year of the zodiac:Metal zodiac:Rabbit
Sexagenary cycle position 28 of 60. Lunar new year falls in late January / mid-February.
- Buddhist Era
-
2074 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
- Persian Solar Hijri
-
909 / 910 SH
Iranian calendar; Nowruz (new year) falls on the spring equinox.
- Ethiopian
-
1523 / 1524 ET
Year boundary at Enkutatash (September 11/12).
- Indian National (Saka)
-
1453 / 1452 Saka
Indian national calendar; year starts in March.
Properties
Primality
1,531 is prime. It has exactly two divisors: 1 and itself.
Divisors & multiples
Sums & aliquot sequence
Continued fraction of √n
√1,531 = [39; (7, 1, 4, 2, 1, 12, 2, 1, 4, 1, 1, 5, 2, 8, 4, 4, 2, 1, 3, 2, 2, 1, 25, 2, …)]
Period length 58 — the block in parentheses repeats forever.
Representations
- In words
- one thousand five hundred thirty-one
- Ordinal
- 1531st
- Roman numeral
- MDXXXI
- Binary
- 10111111011
- Octal
- 2773
- Hexadecimal
- 0x5FB
- Base64
- Bfs=
- One's complement
- 64,004 (16-bit)
- Scientific notation
- 1.531 × 10³
- As a duration
- 1,531 s = 25 minutes, 31 seconds
As an angle
Historical numeral systems
- Babylonian (base 60)
- 𒌋𒌋𒁹𒁹𒁹𒁹𒁹 𒌋𒌋𒌋𒁹
- Egyptian hieroglyphic
- 𓆼𓍢𓍢𓍢𓍢𓍢𓎆𓎆𓎆𓏺
- Greek (Milesian)
- ͵αφλαʹ
- Mayan (base 20)
- 𝋣·𝋰·𝋫
- Chinese
- 一千五百三十一
- Chinese (financial)
- 壹仟伍佰參拾壹
Digit at this position in famous constants
- π — Pi (π)
- Digit 1,531 = 5
- e — Euler's number (e)
- Digit 1,531 = 7
- φ — Golden ratio (φ)
- Digit 1,531 = 6
- √2 — Pythagoras's (√2)
- Digit 1,531 = 7
- ln 2 — Natural log of 2
- Digit 1,531 = 4
- γ — Euler-Mascheroni (γ)
- Digit 1,531 = 7
Also seen as
As an unsigned 32-bit integer, this is the IPv4 address 0.0.5.251.
- Address
- 0.0.5.251
- Class
- reserved
- IPv4-mapped IPv6
- ::ffff:0.0.5.251
Unspecified address (0.0.0.0/8) — "this network" placeholder.
Heard as a frequency, 1,531 Hz is closest to:
- Concert pitch (A4 = 440 Hz): G6 (1568 Hz, -41¢)
- Scientific pitch (C4 = 256 Hz): G6 (1534.3 Hz, -4¢)
- Baroque pitch (A4 = 415 Hz): G♯6 (1566.8 Hz, -40¢)
The digit sequence 1531 first appears in π at position 29,138 of the decimal expansion (the 29,138ordinal-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.
Related reading
- Prime numbers — The building blocks of arithmetic: what primes are, why they matter, and how we find them.
- Egyptian hieroglyphic numerals — Seven hieroglyphs for every power of ten, from a single stroke to a million.