Number

858

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

Abundant Number Arithmetic Number Evil Number Palindrome Practical Number Recamán's Sequence Semiperfect Number Squarefree Year

Historical context — 858 AD

Calendar year

Year 858 (DCCCLVIII) was a common year starting on Saturday of the Julian calendar.

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Historical context — 858 BC

Decade

This article concerns the period 859 BC – 850 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: Tuesday
January 1, 858
Ended on: Tuesday
December 31, 858
Friday the 13ths: 2
2 Friday the 13ths this year.
Decade: 850s
850–859
Century: 9th century
801–900
Millennium: 1st millennium
1–1000
Years ago: 1,168
1168 years before 2026.

In other calendars

Hebrew: 4618 / 4619 AM
Rosh Hashanah falls in September/October.
Islamic Hijri: 243 / 244 AH
Lunar calendar; year spans differ from Gregorian.
Chinese: Year of the zodiac:Earth zodiac:Tiger
Sexagenary cycle position 15 of 60. Lunar new year falls in late January / mid-February.
Buddhist Era: 1401 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
Persian Solar Hijri: 236 / 237 SH
Iranian calendar; Nowruz (new year) falls on the spring equinox.
Ethiopian: 850 / 851 ET
Year boundary at Enkutatash (September 11/12).
Indian National (Saka): 780 / 779 Saka
Indian national calendar; year starts in March.

Properties

Parity: Even
Digit count: 3
Digit sum: 21
Digit product: 320
Digital root: 3
Palindrome: Yes
Bit width: 10 bits
Recamán's sequence: a(815) = 858
Square (n²): 736,164
Cube (n³): 631,628,712
Divisor count: 16
σ(n) — sum of divisors: 2,016
φ(n) — Euler's totient: 240
Sum of prime factors: 29

Primality

Prime factorization: 2 × 3 × 11 × 13

Nearest primes: 857 (−1) · 859 (+1)

Divisors & multiples

All divisors (16)

1 · 2 · 3 · 6 · 11 · 13 · 22 · 26 · 33 · 39 · 66 · 78 · 143 · 286 · 429 (half) · 858

Aliquot sum (sum of proper divisors): 1,158

Factor pairs (a × b = 858)

1 × 858

2 × 429

3 × 286

6 × 143

11 × 78

13 × 66

22 × 39

26 × 33

First multiples

858 · 1,716 (double) · 2,574 · 3,432 · 4,290 · 5,148 · 6,006 · 6,864 · 7,722 · 8,580

Sums & aliquot sequence

As consecutive integers: 285 + 286 + 287 213 + 214 + 215 + 216 73 + 74 + … + 83 66 + 67 + … + 77

Aliquot sequence: 858 → 1,158 → 1,170 → 2,106 → 2,976 → 5,088 → 8,520 → 17,400 → 38,400 → 88,452 → 196,924 → 228,004 → 255,836 → 255,892 → 339,948 → 708,372 → 1,392,748 — unresolved within range

Representations

In words: eight hundred fifty-eight
Ordinal: 858th
Roman numeral: DCCCLVIII
Binary: 1101011010
Octal: 1532
Hexadecimal: 0x35A
Base64: A1o=
One's complement: 64,677 (16-bit)

In other bases

ternary (3) 1011210

quaternary (4) 31122

quinary (5) 11413

senary (6) 3550

septenary (7) 2334

nonary (9) 1153

undecimal (11) 710

duodecimal (12) 5b6

tridecimal (13) 510

tetradecimal (14) 454

pentadecimal (15) 3c3

Historical numeral systems

Babylonian (base 60): 𒌋𒁹𒁹𒁹𒁹 𒌋𒁹𒁹𒁹𒁹𒁹𒁹𒁹𒁹
Egyptian hieroglyphic: 𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓎆𓎆𓎆𓎆𓎆𓏺𓏺𓏺𓏺𓏺𓏺𓏺𓏺
Greek (Milesian): ωνηʹ
Mayan (base 20): 𝋢·𝋢·𝋲
Chinese: 八百五十八
Chinese (financial): 捌佰伍拾捌

In other modern scripts

Eastern Arabic ٨٥٨ Devanagari ८५८ Bengali ৮৫৮ Tamil ௮௫௮ Thai ๘๕๘ Tibetan ༨༥༨ Khmer ៨៥៨ Lao ໘໕໘ Burmese ၈၅၈

Digit at this position in famous constants

π — Pi (π): Digit 858 = 0
e — Euler's number (e): Digit 858 = 1
φ — Golden ratio (φ): Digit 858 = 4
√2 — Pythagoras's (√2): Digit 858 = 8
ln 2 — Natural log of 2: Digit 858 = 9
γ — Euler-Mascheroni (γ): Digit 858 = 3

Also seen as

Goldbach decomposition

Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 858, here are decompositions:

5 + 853 = 858
19 + 839 = 858
29 + 829 = 858
31 + 827 = 858
37 + 821 = 858
47 + 811 = 858
61 + 797 = 858
71 + 787 = 858

Showing the first eight; more decompositions exist.

Unicode codepoint

Combining Double Ring Below

U+035A

Non-spacing mark (Mn)

UTF-8 encoding: CD 9A (2 bytes).

Lookup U+035A on Compart ↗ Lookup on FileFormat.Info ↗

Hex color

#00035A

RGB(0, 3, 90)

IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.3.90.

Address: 0.0.3.90
Class: reserved
IPv4-mapped IPv6: ::ffff:0.0.3.90

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

NANP area code 858

The number 858 is an active NANP area code (North American Numbering Plan).

Primary area: Northern San Diego
Region: California
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 858 ↗