Number

845

845 is a composite number, odd, a calendar year.

Arithmetic Number Deficient Number Evil Number Recamán's Sequence Year

Historical context — 845 AD

Calendar year

Year 845 (DCCCXLV) was a common year starting on Thursday of the Julian calendar.

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Historical context — 845 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: Sunday
January 1, 845
Ended on: Sunday
December 31, 845
Friday the 13ths: 2
2 Friday the 13ths this year.
Decade: 840s
840–849
Century: 9th century
801–900
Millennium: 1st millennium
1–1000
Years ago: 1,181
1181 years before 2026.

In other calendars

Hebrew: 4605 / 4606 AM
Rosh Hashanah falls in September/October.
Islamic Hijri: 230 / 231 AH
Lunar calendar; year spans differ from Gregorian.
Chinese: Year of the zodiac:Wood zodiac:Ox
Sexagenary cycle position 2 of 60. Lunar new year falls in late January / mid-February.
Buddhist Era: 1388 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
Persian Solar Hijri: 223 / 224 SH
Iranian calendar; Nowruz (new year) falls on the spring equinox.
Ethiopian: 837 / 838 ET
Year boundary at Enkutatash (September 11/12).
Indian National (Saka): 767 / 766 Saka
Indian national calendar; year starts in March.

Properties

Parity: Odd
Digit count: 3
Digit sum: 17
Digit product: 160
Digital root: 8
Palindrome: No
Bit width: 10 bits
Reversed: 548
Recamán's sequence: a(841) = 845
Square (n²): 714,025
Cube (n³): 603,351,125
Divisor count: 6
σ(n) — sum of divisors: 1,098
φ(n) — Euler's totient: 624
Sum of prime factors: 31

Primality

Prime factorization: 5 × 13 ²

Nearest primes: 839 (−6) · 853 (+8)

Divisors & multiples

All divisors (6)

1 · 5 · 13 · 65 · 169 · 845

Aliquot sum (sum of proper divisors): 253

Factor pairs (a × b = 845)

1 × 845

5 × 169

13 × 65

First multiples

845 · 1,690 (double) · 2,535 · 3,380 · 4,225 · 5,070 · 5,915 · 6,760 · 7,605 · 8,450

Sums & aliquot sequence

As a sum of two squares: 2² + 29² = 13² + 26² = 19² + 22²

As consecutive integers: 422 + 423 167 + 168 + 169 + 170 + 171 80 + 81 + … + 89 59 + 60 + … + 71

Aliquot sequence: 845 → 253 → 35 → 13 → 1 → 0 — terminates at zero

Representations

In words: eight hundred forty-five
Ordinal: 845th
Roman numeral: DCCCXLV
Binary: 1101001101
Octal: 1515
Hexadecimal: 0x34D
Base64: A00=
One's complement: 64,690 (16-bit)

In other bases

ternary (3) 1011022

quaternary (4) 31031

quinary (5) 11340

senary (6) 3525

septenary (7) 2315

nonary (9) 1138

undecimal (11) 6a9

duodecimal (12) 5a5

tridecimal (13) 500

tetradecimal (14) 445

pentadecimal (15) 3b5

Historical numeral systems

Babylonian (base 60): 𒌋𒁹𒁹𒁹𒁹 𒁹𒁹𒁹𒁹𒁹
Egyptian hieroglyphic: 𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓎆𓎆𓎆𓎆𓏺𓏺𓏺𓏺𓏺
Greek (Milesian): ωμεʹ
Mayan (base 20): 𝋢·𝋢·𝋥
Chinese: 八百四十五
Chinese (financial): 捌佰肆拾伍

In other modern scripts

Eastern Arabic ٨٤٥ Devanagari ८४५ Bengali ৮৪৫ Tamil ௮௪௫ Thai ๘๔๕ Tibetan ༨༤༥ Khmer ៨៤៥ Lao ໘໔໕ Burmese ၈၄၅

Digit at this position in famous constants

π — Pi (π): Digit 845 = 9
e — Euler's number (e): Digit 845 = 3
φ — Golden ratio (φ): Digit 845 = 2
√2 — Pythagoras's (√2): Digit 845 = 3
ln 2 — Natural log of 2: Digit 845 = 8
γ — Euler-Mascheroni (γ): Digit 845 = 1

Also seen as

Unicode codepoint

Combining Left Right Arrow Below

U+034D

Non-spacing mark (Mn)

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

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

Hex color

#00034D

RGB(0, 3, 77)

IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.3.77.

Address: 0.0.3.77
Class: reserved
IPv4-mapped IPv6: ::ffff:0.0.3.77

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

NANP area code 845

The number 845 is an active NANP area code (North American Numbering Plan).

Primary area: Hudson Valley
Region: New York
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.

Look up area code 845 ↗