Number

79

79 is a prime, odd, a calendar year.

Arithmetic Number Cousin Prime Deficient Number Emirp Happy Number Odious Number Pernicious Number Prime Recamán's Sequence Sexy Prime Squarefree Year

Notable events — 79 AD

Jun 23 Emperor Vespasian dies; his son Titus succeeds him.
Aug 24 Mount Vesuvius erupts, burying Pompeii and Herculaneum.
Undated Pliny the Elder dies during the Vesuvius evacuation.
Undated The Roman fort Deva Victrix — modern Chester — is founded.

Events compiled from Wikipedia ↗ · Licensed CC BY-SA 4.0

Historical context — 79 BC

Calendar year

Year 79 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: Sunday
January 1, 79
Ended on: Sunday
December 31, 79
Friday the 13ths: 2
2 Friday the 13ths this year.
Decade: 70s
70–79
Century: 1st century
1–100
Millennium: 1st millennium
1–1000
Years ago: 1,947
1947 years before 2026.

In other calendars

Hebrew: 3839 / 3840 AM
Rosh Hashanah falls in September/October.
Chinese: Year of the zodiac:Earth zodiac:Rabbit
Sexagenary cycle position 16 of 60. Lunar new year falls in late January / mid-February.
Buddhist Era: 622 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
Ethiopian: 71 / 72 ET
Year boundary at Enkutatash (September 11/12).
Indian National (Saka): 1 / 0 Saka
Indian national calendar; year starts in March.

Properties

Parity: Odd
Digit count: 2
Digit sum: 16
Digit product: 63
Digital root: 7
Palindrome: No
Bit width: 7 bits
Reversed: 97
Recamán's sequence: a(33) = 79
Square (n²): 6,241
Cube (n³): 493,039
Divisor count: 2
σ(n) — sum of divisors: 80
φ(n) — Euler's totient: 78

Primality

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

Divisors & multiples

All divisors (2)

1 · 79

Aliquot sum (sum of proper divisors): 1

Factor pairs (a × b = 79)

1 × 79

First multiples

79 · 158 (double) · 237 · 316 · 395 · 474 · 553 · 632 · 711 · 790

Sums & aliquot sequence

As consecutive integers: 39 + 40

Representations

In words: seventy-nine
Ordinal: 79th
Roman numeral: LXXIX
Binary: 1001111
Octal: 117
Hexadecimal: 0x4F
Base64: Tw==
One's complement: 176 (8-bit)

In other bases

ternary (3) 2221

quaternary (4) 1033

quinary (5) 304

senary (6) 211

septenary (7) 142

nonary (9) 87

undecimal (11) 72

duodecimal (12) 67

tridecimal (13) 61

tetradecimal (14) 59

pentadecimal (15) 54

Historical numeral systems

Babylonian (base 60): 𒁹 𒌋𒁹𒁹𒁹𒁹𒁹𒁹𒁹𒁹𒁹
Egyptian hieroglyphic: 𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓏺𓏺𓏺𓏺𓏺𓏺𓏺𓏺𓏺
Greek (Milesian): οθʹ
Mayan (base 20): 𝋣·𝋳
Chinese: 七十九
Chinese (financial): 柒拾玖

In other modern scripts

Eastern Arabic ٧٩ Devanagari ७९ Bengali ৭৯ Tamil ௭௯ Thai ๗๙ Tibetan ༧༩ Khmer ៧៩ Lao ໗໙ Burmese ၇၉

Digit at this position in famous constants

π — Pi (π): Digit 79 = 8
e — Euler's number (e): Digit 79 = 7
φ — Golden ratio (φ): Digit 79 = 2
√2 — Pythagoras's (√2): Digit 79 = 7
ln 2 — Natural log of 2: Digit 79 = 4
γ — Euler-Mascheroni (γ): Digit 79 = 4

Also seen as

Prime neighborhood

Adjacent primes:

Previous prime: 73 (gap of 6)
Next prime: 83 (gap of 4)

Pair status: cousin with 83, sexy with 73.

ASCII character

As an ASCII codepoint, 79 is O. Printable ASCII character O.

Hex color

#00004F

RGB(0, 0, 79)

IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.0.79.

Address: 0.0.0.79
Class: reserved
IPv4-mapped IPv6: ::ffff:0.0.0.79

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

US numbered highway

Matches numbered highway designation:

I-79 — Charleston, WV to Erie, PA.

Interstate 79 on Wikipedia ↗