Number

5

5 is a prime, odd, a calendar year.

Arithmetic Number Automorphic Number Balanced Prime Bell Number Catalan Number Chen Prime Deficient Number Evil Number Fermat Number Fibonacci Harshad / Niven Narcissistic / Armstrong Padovan Number Pell Number Pentagonal Pernicious Number Perrin Number Prime Pythagorean Prime Recamán's Sequence Safe Prime Self Number Sexy Prime Sophie Germain Prime Square Pyramidal Squarefree Twin Prime Year Zuckerman Number

Historical context — 5 BC

Calendar year

5 BC was a common year starting on Monday or Tuesday of the Julian calendar and a leap year starting on Saturday of the Proleptic Julian 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: Saturday
January 1, 5
Ended on: Saturday
December 31, 5
Friday the 13ths: 1
One Friday the 13th this year.
Decade: 0s
0–9
Century: 1st century
1–100
Millennium: 1st millennium
1–1000
Years ago: 2,021
2021 years before 2026.

In other calendars

Hebrew: 3765 / 3766 AM
Rosh Hashanah falls in September/October.
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: 548 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
Ethiopian: -3 / -2 ET
Year boundary at Enkutatash (September 11/12).
Indian National (Saka): -73 / -74 Saka
Indian national calendar; year starts in March.

Cultural significance

Chinese significant

Associated with the Five Elements (wood, fire, earth, metal, water).

Wǔxíng — the foundational schema of traditional Chinese cosmology.

Islamic sacred

The Five Pillars of Islam.

Shahada, prayer, alms, fasting, pilgrimage.

Sourced from Wikipedia (Numerology, Chinese numerology, Gematria, and per-culture articles).

Properties

Parity: Odd
Digit count: 1
Digit sum: 5
Digital root: 5
Palindrome: Yes
Bit width: 3 bits
Recamán's sequence: a(129) = 5
Square (n²): 25
Cube (n³): 125
Divisor count: 2
σ(n) — sum of divisors: 6
φ(n) — Euler's totient: 4

Primality

5 is prime. It has exactly two divisors: 1 and itself.

Divisors & multiples

All divisors (2)

1 · 5

Aliquot sum (sum of proper divisors): 1

Factor pairs (a × b = 5)

1 × 5

First multiples

5 · 10 (double) · 15 · 20 · 25 · 30 · 35 · 40 · 45 · 50

Sums & aliquot sequence

As a sum of two squares: 1² + 2²

As consecutive integers: 2 + 3

Representations

In words: five
Ordinal: 5th
Roman numeral: V
Binary: 101
Octal: 5
Hexadecimal: 0x5
Base64: BQ==
One's complement: 250 (8-bit)

In other bases

ternary (3) 12

quaternary (4) 11

quinary (5) 10

senary (6) 5

septenary (7) 5

nonary (9) 5

undecimal (11) 5

duodecimal (12) 5

tridecimal (13) 5

tetradecimal (14) 5

pentadecimal (15) 5

Historical numeral systems

Babylonian (base 60): 𒁹𒁹𒁹𒁹𒁹
Egyptian hieroglyphic: 𓏺𓏺𓏺𓏺𓏺
Greek (Milesian): εʹ
Mayan (base 20): 𝋥
Chinese: 五
Chinese (financial): 伍

In other modern scripts

Eastern Arabic ٥ Devanagari ५ Bengali ৫ Tamil ௫ Thai ๕ Tibetan ༥ Khmer ៥ Lao ໕ Burmese ၅

Digit at this position in famous constants

π — Pi (π): Digit 5 = 5
e — Euler's number (e): Digit 5 = 2
φ — Golden ratio (φ): Digit 5 = 0
√2 — Pythagoras's (√2): Digit 5 = 2
ln 2 — Natural log of 2: Digit 5 = 1
γ — Euler-Mascheroni (γ): Digit 5 = 2

Also seen as

Prime neighborhood

Adjacent primes:

Previous prime: 3 (gap of 2)
Next prime: 7 (gap of 2)

Pair status: twin with 3, twin with 7.

ASCII character

As an ASCII codepoint, 5 is control character (0x05). ASCII control character.

Hex color

#000005

RGB(0, 0, 5)

IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.0.5.

Address: 0.0.0.5
Class: reserved
IPv4-mapped IPv6: ::ffff:0.0.0.5

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

US numbered highway

Matches numbered highway designation:

I-5 — Mexico border (San Diego) to Canada border (Blaine, WA) — the Pacific coast spine.

Interstate 5 on Wikipedia ↗