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Number

1,618

1,618 is a composite number, even, a calendar year.

Deficient Number Flippable Odious Number Pernicious Number Recamán's Sequence Semiprime Squarefree Year

Notable events — 1618 AD

  1. May 23 The Defenestration of Prague sparks the Thirty Years' War.
  2. Oct 29 Sir Walter Raleigh is executed in England.
  3. Sep 14 Kepler publishes the third of his laws of planetary motion.

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
52
Started on
Monday
January 1, 1618
Ended on
Monday
December 31, 1618
Friday the 13ths
2
2 Friday the 13ths this year.
Easter Sunday
April 15
Sunday, April 15, 1618
Decade
1610s
1610–1619
Century
17th century
1601–1700
Millennium
2nd millennium
1001–2000
Years ago
408
408 years before 2026.

In other calendars

Hebrew
5378 / 5379 AM
Rosh Hashanah falls in September/October.
Islamic Hijri
1027 / 1028 AH
Lunar calendar; year spans differ from Gregorian.
Chinese
Year of the zodiac:Earth zodiac:Horse
Sexagenary cycle position 55 of 60. Lunar new year falls in late January / mid-February.
Buddhist Era
2161 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
Persian Solar Hijri
996 / 997 SH
Iranian calendar; Nowruz (new year) falls on the spring equinox.
Ethiopian
1610 / 1611 ET
Year boundary at Enkutatash (September 11/12).
Indian National (Saka)
1540 / 1539 Saka
Indian national calendar; year starts in March.

Properties

Parity
Even
Digit count
4
Digit sum
16
Digit product
48
Digital root
7
Palindrome
No
Bit width
11 bits
Reversed
8,161
Flips to (rotate 180°)
8,191
Recamán's sequence
a(716) = 1,618
Square (n²)
2,617,924
Cube (n³)
4,235,801,032
Divisor count
4
σ(n) — sum of divisors
2,430
φ(n) — Euler's totient
808
Sum of prime factors
811

Primality

Prime factorization: 2 × 809

Nearest primes: 1,613 (−5) · 1,619 (+1)

Divisors & multiples

All divisors (4)
1 · 2 · 809 (half) · 1618
Aliquot sum (sum of proper divisors): 812
Factor pairs (a × b = 1,618)
1 × 1618
2 × 809
First multiples
1,618 · 3,236 (double) · 4,854 · 6,472 · 8,090 · 9,708 · 11,326 · 12,944 · 14,562 · 16,180

Sums & aliquot sequence

As a sum of two squares: 23² + 33²
As consecutive integers: 403 + 404 + 405 + 406
Aliquot sequence: 1,618 812 868 924 1,764 3,423 1,825 469 75 49 8 7 1 0 — terminates at zero

Representations

In words
one thousand six hundred eighteen
Ordinal
1618th
Roman numeral
MDCXVIII
Binary
11001010010
Octal
3122
Hexadecimal
0x652
Base64
BlI=
One's complement
63,917 (16-bit)
In other bases
ternary (3) 2012221
quaternary (4) 121102
quinary (5) 22433
senary (6) 11254
septenary (7) 4501
nonary (9) 2187
undecimal (11) 1241
duodecimal (12) b2a
tridecimal (13) 976
tetradecimal (14) 838
pentadecimal (15) 72d

Historical numeral systems

Babylonian (base 60)
𒌋𒌋𒁹𒁹𒁹𒁹𒁹𒁹 𒌋𒌋𒌋𒌋𒌋𒁹𒁹𒁹𒁹𒁹𒁹𒁹𒁹
Egyptian hieroglyphic
𓆼𓍢𓍢𓍢𓍢𓍢𓍢𓎆𓏺𓏺𓏺𓏺𓏺𓏺𓏺𓏺
Greek (Milesian)
͵αχιηʹ
Mayan (base 20)
𝋤·𝋠·𝋲
Chinese
一千六百一十八
Chinese (financial)
壹仟陸佰壹拾捌
In other modern scripts
Eastern Arabic ١٦١٨ Devanagari १६१८ Bengali ১৬১৮ Tamil ௧௬௧௮ Thai ๑๖๑๘ Tibetan ༡༦༡༨ Khmer ១៦១៨ Lao ໑໖໑໘ Burmese ၁၆၁၈

Digit at this position in famous constants

π — Pi (π)
Digit 1,618 = 9
e — Euler's number (e)
Digit 1,618 = 5
φ — Golden ratio (φ)
Digit 1,618 = 2
√2 — Pythagoras's (√2)
Digit 1,618 = 2
ln 2 — Natural log of 2
Digit 1,618 = 2
γ — Euler-Mascheroni (γ)
Digit 1,618 = 4

Also seen as

Goldbach decomposition

Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 1618, here are decompositions:

  • 5 + 1613 = 1618
  • 11 + 1607 = 1618
  • 17 + 1601 = 1618
  • 47 + 1571 = 1618
  • 59 + 1559 = 1618
  • 107 + 1511 = 1618
  • 131 + 1487 = 1618
  • 137 + 1481 = 1618

Showing the first eight; more decompositions exist.

Unicode codepoint
ْ
Arabic Sukun
U+0652
Non-spacing mark (Mn)

UTF-8 encoding: D9 92 (2 bytes).

Hex color
#000652
RGB(0, 6, 82)
IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.6.82.

Address
0.0.6.82
Class
reserved
IPv4-mapped IPv6
::ffff:0.0.6.82

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

Position in π

The digit sequence 1618 first appears in π at position 6,004 of the decimal expansion (the 6,004ordinal-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.