Live analysis

3,981

3,981 is a composite number, odd.

This number doesn't have a permanent NumberWiki page yet — what you see below is computed live. Pages get added to the permanent index when they're notable (years, primes, curated, etc.).

3,981 (three thousand nine hundred eighty-one) is an odd 4-digit number. It is a composite number with 4 divisors, and factors as 3 × 1,327. Written other ways, in Roman numerals it is MMMCMLXXXI and in binary, 111110001101.

Arithmetic Number Cube-Free Deficient Number Evil Number Recamán's Sequence Semiprime Squarefree

Interestingness

★ ★ ★ ☆ ☆

5 notable facts · grade C

3,969 3,970 3,971 3,972 3,973 3,974 3,975 3,976 3,977 3,978 3,979 3,980 3,981 3,982 3,983 3,984 3,985 3,986 3,987 3,988 3,989 3,990 3,991 3,992 3,993

less more

Properties

Parity: Odd
Digit count: 4
Digit sum: 21
Digit product: 216
Digital root: 3
Palindrome: No
Bit width: 12 bits
Reversed: 1,893
Recamán's sequence: a(14,429) = 3,981
Square (n²): 15,848,361
Cube (n³): 63,092,325,141
Divisor count: 4
σ(n) — sum of divisors: 5,312
φ(n) — Euler's totient: 2,652
Sum of prime factors: 1,330

Primality

Prime factorization: 3 × 1327

Nearest primes: 3,967 (−14) · 3,989 (+8)

Divisors & multiples

All divisors (4)

1 · 3 · 1327 · 3981

Aliquot sum (sum of proper divisors): 1,331

Factor pairs (a × b = 3,981)

1 × 3981

3 × 1327

First multiples

3,981 · 7,962 (double) · 11,943 · 15,924 · 19,905 · 23,886 · 27,867 · 31,848 · 35,829 · 39,810

Sums & aliquot sequence

As consecutive integers: 1,990 + 1,991 1,326 + 1,327 + 1,328 661 + 662 + 663 + 664 + 665 + 666

Aliquot sequence: 3,981 → 1,331 → 133 → 27 → 13 → 1 → 0 — terminates at zero

Continued fraction of √n

√3,981 = [63; (10, 1, 1, 31, 42, 31, 1, 1, 10, 126)]

Period length 10 — the block in parentheses repeats forever.

Representations

In words: three thousand nine hundred eighty-one
Ordinal: 3981st
Roman numeral: MMMCMLXXXI
Binary: 111110001101
Octal: 7615
Hexadecimal: 0xF8D
Base64: D40=
One's complement: 61,554 (16-bit)
Scientific notation: 3.981 × 10³
As a duration: 3,981 s = 1 hour, 6 minutes, 21 seconds

In other bases

ternary (3) 12110110

quaternary (4) 332031

quinary (5) 111411

senary (6) 30233

septenary (7) 14415

nonary (9) 5413

undecimal (11) 2a9a

duodecimal (12) 2379

tridecimal (13) 1a73

tetradecimal (14) 1645

pentadecimal (15) 12a6

As an angle

3,981° = 11 × 360° + 21°

21° ≈ 0.367 rad

Compass bearing: NNE (north-northeast)

Why does a circle have 360 degrees? →

Historical numeral systems

Babylonian (base 60): 𒁹 𒁹𒁹𒁹𒁹𒁹𒁹 𒌋𒌋𒁹
Egyptian hieroglyphic: 𓆼𓆼𓆼𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓏺
Greek (Milesian): ͵γϡπαʹ
Mayan (base 20): 𝋩·𝋳·𝋡
Chinese: 三千九百八十一
Chinese (financial): 參仟玖佰捌拾壹

In other modern scripts

Eastern Arabic ٣٩٨١ Devanagari ३९८१ Bengali ৩৯৮১ Tamil ௩௯௮௧ Thai ๓๙๘๑ Tibetan ༣༩༨༡ Khmer ៣៩៨១ Lao ໓໙໘໑ Burmese ၃၉၈၁

Digit at this position in famous constants

π — Pi (π): Digit 3,981 = 2
e — Euler's number (e): Digit 3,981 = 2
φ — Golden ratio (φ): Digit 3,981 = 0
√2 — Pythagoras's (√2): Digit 3,981 = 0
ln 2 — Natural log of 2: Digit 3,981 = 0
γ — Euler-Mascheroni (γ): Digit 3,981 = 0

Also seen as

Unicode codepoint

ྍ

Tibetan Subjoined Sign Lce Tsa Can

U+0F8D

Non-spacing mark (Mn)

UTF-8 encoding: E0 BE 8D (3 bytes).

Lookup U+0F8D on Compart ↗ Lookup on FileFormat.Info ↗

Hex color

#000F8D

RGB(0, 15, 141)

IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.15.141.

Address: 0.0.15.141
Class: reserved
IPv4-mapped IPv6: ::ffff:0.0.15.141

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

Musical pitch

Heard as a frequency, 3,981 Hz is closest to:

Concert pitch (A4 = 440 Hz): B7 (3951.1 Hz, +13¢)
Scientific pitch (C4 = 256 Hz): C8 (4096 Hz, -49¢ — about midway to B7)
Baroque pitch (A4 = 415 Hz): C8 (3948.2 Hz, +14¢)

Position in π

The digit sequence 3981 first appears in π at position 12,191 of the decimal expansion (the 12,191ordinal-suffix:st digit after the integer 3).

Search range: the first 1,000,000 fractional digits of π. Any 6-digit-or-shorter string is virtually guaranteed to appear in there — the more interesting signal is the position.

Look up 3981 on Pi Search ↗