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Number

87

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

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

Historical context — 87 AD

Calendar year

AD 87 (LXXXVII) was a common year starting on Monday of the Julian calendar.

Excerpt from Wikipedia (en) ↗ · Licensed CC BY-SA 4.0 · English fallback Read the full article on Wikipedia →

Historical context — 87 BC

Calendar year

Year 87 BC was a year of the pre-Julian Roman calendar.

Excerpt from Wikipedia (en) ↗ · Licensed CC BY-SA 4.0 · English fallback Read the full article on Wikipedia →

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, 87
Ended on: Wednesday
December 31, 87
Friday the 13ths: 1
One Friday the 13th this year.
Decade: 80s
80–89
Century: 1st century
1–100
Millennium: 1st millennium
1–1000
Years ago: 1,939
1939 years before 2026.

In other calendars

Hebrew: 3847 / 3848 AM
Rosh Hashanah falls in September/October.
Chinese: Year of the zodiac:Fire zodiac:Pig
Sexagenary cycle position 24 of 60. Lunar new year falls in late January / mid-February.
Buddhist Era: 630 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
Ethiopian: 79 / 80 ET
Year boundary at Enkutatash (September 11/12).
Indian National (Saka): 9 / 8 Saka
Indian national calendar; year starts in March.

Properties

Parity: Odd
Digit count: 2
Digit sum: 15
Digit product: 56
Digital root: 6
Palindrome: No
Bit width: 7 bits
Reversed: 78
Recamán's sequence: a(57) = 87
Square (n²): 7,569
Cube (n³): 658,503
Divisor count: 4
σ(n) — sum of divisors: 120
φ(n) — Euler's totient: 56
Sum of prime factors: 32

Primality

Prime factorization: 3 × 29

Nearest primes: 83 (−4) · 89 (+2)

Divisors & multiples

All divisors (4)

1 · 3 · 29 · 87

Aliquot sum (sum of proper divisors): 33

Factor pairs (a × b = 87)

1 × 87

3 × 29

First multiples

87 · 174 (double) · 261 · 348 · 435 · 522 · 609 · 696 · 783 · 870

Sums & aliquot sequence

As consecutive integers: 43 + 44 28 + 29 + 30 12 + 13 + 14 + 15 + 16 + 17

Aliquot sequence: 87 → 33 → 15 → 9 → 4 → 3 → 1 → 0 — terminates at zero

Representations

In words: eighty-seven
Ordinal: 87th
Roman numeral: LXXXVII
Binary: 1010111
Octal: 127
Hexadecimal: 0x57
Base64: Vw==
One's complement: 168 (8-bit)

In other bases

ternary (3) 10020

quaternary (4) 1113

quinary (5) 322

senary (6) 223

septenary (7) 153

nonary (9) 106

undecimal (11) 7a

duodecimal (12) 73

tridecimal (13) 69

tetradecimal (14) 63

pentadecimal (15) 5c

Historical numeral systems

Babylonian (base 60): 𒁹 𒌋𒌋𒁹𒁹𒁹𒁹𒁹𒁹𒁹
Egyptian hieroglyphic: 𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓏺𓏺𓏺𓏺𓏺𓏺𓏺
Greek (Milesian): πζʹ
Mayan (base 20): 𝋤·𝋧
Chinese: 八十七
Chinese (financial): 捌拾柒

In other modern scripts

Eastern Arabic ٨٧ Devanagari ८७ Bengali ৮৭ Tamil ௮௭ Thai ๘๗ Tibetan ༨༧ Khmer ៨៧ Lao ໘໗ Burmese ၈၇

Digit at this position in famous constants

π — Pi (π): Digit 87 = 3
e — Euler's number (e): Digit 87 = 8
φ — Golden ratio (φ): Digit 87 = 0
√2 — Pythagoras's (√2): Digit 87 = 8
ln 2 — Natural log of 2: Digit 87 = 6
γ — Euler-Mascheroni (γ): Digit 87 = 4

Also seen as

ASCII character

As an ASCII codepoint, 87 is W. Printable ASCII character W.

Hex color

#000057

RGB(0, 0, 87)

IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.0.87.

Address: 0.0.0.87
Class: reserved
IPv4-mapped IPv6: ::ffff:0.0.0.87

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

US numbered highway

Matches numbered highway designation:

I-87 — New York City to Champlain, NY (Canadian border).

Interstate 87 on Wikipedia ↗