Number

842

842 is a composite number, even, a calendar year.

Deficient Number Descending Digits Odious Number Pernicious Number Recamán's Sequence Semiprime Squarefree Year

Historical context — 842 AD

Calendar year

Year 842 (DCCCXLII) was a common year starting on Sunday of the Julian calendar, the 842nd year of the Common Era (CE) and Anno Domini (AD) designations, the 842nd year of the 1st millennium, the 42nd year of the 9th century, and the 3rd year of the 840s decade.

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Historical context — 842 BC

Decade

This article concerns the period 849 BC – 840 BC.

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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: Wednesday
January 1, 842
Ended on: Wednesday
December 31, 842
Friday the 13ths: 1
One Friday the 13th this year.
Decade: 840s
840–849
Century: 9th century
801–900
Millennium: 1st millennium
1–1000
Years ago: 1,184
1184 years before 2026.

In other calendars

Hebrew: 4602 / 4603 AM
Rosh Hashanah falls in September/October.
Islamic Hijri: 227 / 228 AH
Lunar calendar; year spans differ from Gregorian.
Chinese: Year of the zodiac:Water zodiac:Dog
Sexagenary cycle position 59 of 60. Lunar new year falls in late January / mid-February.
Buddhist Era: 1385 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
Persian Solar Hijri: 220 / 221 SH
Iranian calendar; Nowruz (new year) falls on the spring equinox.
Ethiopian: 834 / 835 ET
Year boundary at Enkutatash (September 11/12).
Indian National (Saka): 764 / 763 Saka
Indian national calendar; year starts in March.

Properties

Parity: Even
Digit count: 3
Digit sum: 14
Digit product: 64
Digital root: 5
Palindrome: No
Bit width: 10 bits
Reversed: 248
Recamán's sequence: a(339) = 842
Square (n²): 708,964
Cube (n³): 596,947,688
Divisor count: 4
σ(n) — sum of divisors: 1,266
φ(n) — Euler's totient: 420
Sum of prime factors: 423

Primality

Prime factorization: 2 × 421

Nearest primes: 839 (−3) · 853 (+11)

Divisors & multiples

All divisors (4)

1 · 2 · 421 (half) · 842

Aliquot sum (sum of proper divisors): 424

Factor pairs (a × b = 842)

1 × 842

2 × 421

First multiples

842 · 1,684 (double) · 2,526 · 3,368 · 4,210 · 5,052 · 5,894 · 6,736 · 7,578 · 8,420

Sums & aliquot sequence

As a sum of two squares: 1² + 29²

As consecutive integers: 209 + 210 + 211 + 212

Aliquot sequence: 842 → 424 → 386 → 196 → 203 → 37 → 1 → 0 — terminates at zero

Representations

In words: eight hundred forty-two
Ordinal: 842nd
Roman numeral: DCCCXLII
Binary: 1101001010
Octal: 1512
Hexadecimal: 0x34A
Base64: A0o=
One's complement: 64,693 (16-bit)

In other bases

ternary (3) 1011012

quaternary (4) 31022

quinary (5) 11332

senary (6) 3522

septenary (7) 2312

nonary (9) 1135

undecimal (11) 6a6

duodecimal (12) 5a2

tridecimal (13) 4ca

tetradecimal (14) 442

pentadecimal (15) 3b2

Historical numeral systems

Babylonian (base 60): 𒌋𒁹𒁹𒁹𒁹 𒁹𒁹
Egyptian hieroglyphic: 𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓎆𓎆𓎆𓎆𓏺𓏺
Greek (Milesian): ωμβʹ
Mayan (base 20): 𝋢·𝋢·𝋢
Chinese: 八百四十二
Chinese (financial): 捌佰肆拾貳

In other modern scripts

Eastern Arabic ٨٤٢ Devanagari ८४२ Bengali ৮৪২ Tamil ௮௪௨ Thai ๘๔๒ Tibetan ༨༤༢ Khmer ៨៤២ Lao ໘໔໒ Burmese ၈၄၂

Digit at this position in famous constants

π — Pi (π): Digit 842 = 2
e — Euler's number (e): Digit 842 = 3
φ — Golden ratio (φ): Digit 842 = 5
√2 — Pythagoras's (√2): Digit 842 = 4
ln 2 — Natural log of 2: Digit 842 = 1
γ — Euler-Mascheroni (γ): Digit 842 = 3

Also seen as

Goldbach decomposition

Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 842, here are decompositions:

3 + 839 = 842
13 + 829 = 842
19 + 823 = 842
31 + 811 = 842
73 + 769 = 842
103 + 739 = 842
109 + 733 = 842
151 + 691 = 842

Showing the first eight; more decompositions exist.

Unicode codepoint

Combining Not Tilde Above

U+034A

Non-spacing mark (Mn)

UTF-8 encoding: CD 8A (2 bytes).

Lookup U+034A on Compart ↗ Lookup on FileFormat.Info ↗

Hex color

#00034A

RGB(0, 3, 74)

IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.3.74.

Address: 0.0.3.74
Class: reserved
IPv4-mapped IPv6: ::ffff:0.0.3.74

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