Number

47

47 is a prime, odd, a calendar year.

Arithmetic Number Chen Prime Cousin Prime Deficient Number Keith Number Lucas Odious Number Pernicious Number Prime Recamán's Sequence Safe Prime Sexy Prime Squarefree Year

Historical context — 47 AD

Calendar year

AD 47 (XLVII) was a common year starting on Sunday of the Julian calendar.

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Historical context — 47 BC

Calendar year

Year 47 BC was a year of the pre-Julian Roman calendar.

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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, 47
Ended on: Tuesday
December 31, 47
Friday the 13ths: 2
2 Friday the 13ths this year.
Decade: 40s
40–49
Century: 1st century
1–100
Millennium: 1st millennium
1–1000
Years ago: 1,979
1979 years before 2026.

In other calendars

Hebrew: 3807 / 3808 AM
Rosh Hashanah falls in September/October.
Chinese: Year of the zodiac:Fire zodiac:Goat
Sexagenary cycle position 44 of 60. Lunar new year falls in late January / mid-February.
Buddhist Era: 590 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
Ethiopian: 39 / 40 ET
Year boundary at Enkutatash (September 11/12).
Indian National (Saka): -31 / -32 Saka
Indian national calendar; year starts in March.

Properties

Parity: Odd
Digit count: 2
Digit sum: 11
Digit product: 28
Digital root: 2
Palindrome: No
Bit width: 6 bits
Reversed: 74
Recamán's sequence: a(222) = 47
Square (n²): 2,209
Cube (n³): 103,823
Divisor count: 2
σ(n) — sum of divisors: 48
φ(n) — Euler's totient: 46

Primality

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

Divisors & multiples

All divisors (2)

1 · 47

Aliquot sum (sum of proper divisors): 1

Factor pairs (a × b = 47)

1 × 47

First multiples

47 · 94 (double) · 141 · 188 · 235 · 282 · 329 · 376 · 423 · 470

Sums & aliquot sequence

As consecutive integers: 23 + 24

Representations

In words: forty-seven
Ordinal: 47th
Roman numeral: XLVII
Binary: 101111
Octal: 57
Hexadecimal: 0x2F
Base64: Lw==
One's complement: 208 (8-bit)

In other bases

ternary (3) 1202

quaternary (4) 233

quinary (5) 142

senary (6) 115

septenary (7) 65

nonary (9) 52

undecimal (11) 43

duodecimal (12) 3b

tridecimal (13) 38

tetradecimal (14) 35

pentadecimal (15) 32

Historical numeral systems

Babylonian (base 60): 𒌋𒌋𒌋𒌋𒁹𒁹𒁹𒁹𒁹𒁹𒁹
Egyptian hieroglyphic: 𓎆𓎆𓎆𓎆𓏺𓏺𓏺𓏺𓏺𓏺𓏺
Greek (Milesian): μζʹ
Mayan (base 20): 𝋢·𝋧
Chinese: 四十七
Chinese (financial): 肆拾柒

In other modern scripts

Eastern Arabic ٤٧ Devanagari ४७ Bengali ৪৭ Tamil ௪௭ Thai ๔๗ Tibetan ༤༧ Khmer ៤៧ Lao ໔໗ Burmese ၄၇

Digit at this position in famous constants

π — Pi (π): Digit 47 = 3
e — Euler's number (e): Digit 47 = 6
φ — Golden ratio (φ): Digit 47 = 8
√2 — Pythagoras's (√2): Digit 47 = 3
ln 2 — Natural log of 2: Digit 47 = 3
γ — Euler-Mascheroni (γ): Digit 47 = 9

Also seen as

Prime neighborhood

Adjacent primes:

Previous prime: 43 (gap of 4)
Next prime: 53 (gap of 6)

Pair status: cousin with 43, sexy with 53.

ASCII character

As an ASCII codepoint, 47 is /. Printable ASCII character /.

Hex color

#00002F

RGB(0, 0, 47)

IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.0.47.

Address: 0.0.0.47
Class: reserved
IPv4-mapped IPv6: ::ffff:0.0.0.47

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