Number

73

73 is a prime, odd, a calendar year.

Arithmetic Number Binary Palindrome Deficient Number Emirp Odious Number Pernicious Number Prime Pythagorean Prime Recamán's Sequence Sexy Prime Squarefree Twin Prime Year

Historical context — 73 AD

Calendar year

AD 73 (LXXIII) was a common year starting on Friday of the Julian calendar.

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

Notable events — 73 BC

Undated Spartacus and 70 fellow gladiators escape at Capua, beginning the Third Servile War.

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

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, 73
Ended on: Sunday
December 31, 73
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: 1,953
1953 years before 2026.

In other calendars

Hebrew: 3833 / 3834 AM
Rosh Hashanah falls in September/October.
Chinese: Year of the zodiac:Water zodiac:Rooster
Sexagenary cycle position 10 of 60. Lunar new year falls in late January / mid-February.
Buddhist Era: 616 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
Ethiopian: 65 / 66 ET
Year boundary at Enkutatash (September 11/12).
Indian National (Saka): -5 / -6 Saka
Indian national calendar; year starts in March.

Properties

Parity: Odd
Digit count: 2
Digit sum: 10
Digit product: 21
Digital root: 1
Palindrome: No
Bit width: 7 bits
Reversed: 37
Recamán's sequence: a(81) = 73
Square (n²): 5,329
Cube (n³): 389,017
Divisor count: 2
σ(n) — sum of divisors: 74
φ(n) — Euler's totient: 72

Primality

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

Divisors & multiples

All divisors (2)

1 · 73

Aliquot sum (sum of proper divisors): 1

Factor pairs (a × b = 73)

1 × 73

First multiples

73 · 146 (double) · 219 · 292 · 365 · 438 · 511 · 584 · 657 · 730

Sums & aliquot sequence

As a sum of two squares: 3² + 8²

As consecutive integers: 36 + 37

Representations

In words: seventy-three
Ordinal: 73rd
Roman numeral: LXXIII
Binary: 1001001
Octal: 111
Hexadecimal: 0x49
Base64: SQ==
One's complement: 182 (8-bit)
Scientific notation: 7.3 × 10¹

In other bases

ternary (3) 2201

quaternary (4) 1021

quinary (5) 243

senary (6) 201

septenary (7) 133

nonary (9) 81

undecimal (11) 67

duodecimal (12) 61

tridecimal (13) 58

tetradecimal (14) 53

pentadecimal (15) 4d

Palindromic in base 2, base 8

Historical numeral systems

Babylonian (base 60): 𒁹 𒌋𒁹𒁹𒁹
Egyptian hieroglyphic: 𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓏺𓏺𓏺
Greek (Milesian): ογʹ
Mayan (base 20): 𝋣·𝋭
Chinese: 七十三
Chinese (financial): 柒拾參

In other modern scripts

Eastern Arabic ٧٣ Devanagari ७३ Bengali ৭৩ Tamil ௭௩ Thai ๗๓ Tibetan ༧༣ Khmer ៧៣ Lao ໗໓ Burmese ၇၃

Digit at this position in famous constants

π — Pi (π): Digit 73 = 6
e — Euler's number (e): Digit 73 = 0
φ — Golden ratio (φ): Digit 73 = 2
√2 — Pythagoras's (√2): Digit 73 = 8
ln 2 — Natural log of 2: Digit 73 = 1
γ — Euler-Mascheroni (γ): Digit 73 = 6

Also seen as

Prime neighborhood

Adjacent primes:

Previous prime: 71 (gap of 2)
Next prime: 79 (gap of 6)

Pair status: twin with 71, sexy with 79.

ASCII character

As an ASCII codepoint, 73 is I. Printable ASCII character I.

Hex color

#000049

RGB(0, 0, 73)

IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.0.73.

Address: 0.0.0.73
Class: reserved
IPv4-mapped IPv6: ::ffff:0.0.0.73

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

US numbered highway

Matches numbered highway designation:

I-73 — Candor to Greensboro, NC.

Interstate 73 on Wikipedia ↗