Number

8,681

8,681 is a prime, odd.

8,681 (eight thousand six hundred eighty-one) is an odd 4-digit number. It is a prime number — divisible only by 1 and itself. Written other ways, in hexadecimal, 0x21E9.

Arithmetic Number Chen Prime Cousin Prime Cube-Free Deficient Number Flippable Odious Number Pernicious Number Prime Pythagorean Prime Recamán's Sequence Squarefree

Interestingness

★ ★ ★ ★ ★

9 notable facts · grade A

8,669 8,670 8,671 8,672 8,673 8,674 8,675 8,676 8,677 8,678 8,679 8,680 8,681 8,682 8,683 8,684 8,685 8,686 8,687 8,688 8,689 8,690 8,691 8,692 8,693

less more

Properties

Parity: Odd
Digit count: 4
Digit sum: 23
Digit product: 384
Digital root: 5
Palindrome: No
Bit width: 14 bits
Reversed: 1,868
Flips to (rotate 180°): 1,898
Recamán's sequence: a(9,953) = 8,681
Square (n²): 75,359,761
Cube (n³): 654,198,085,241
Divisor count: 2
σ(n) — sum of divisors: 8,682
φ(n) — Euler's totient: 8,680

Primality

8,681 is prime. It has exactly two divisors: 1 and itself.

Divisors & multiples

All divisors (2)

1 · 8681

Aliquot sum (sum of proper divisors): 1

Factor pairs (a × b = 8,681)

1 × 8681

First multiples

8,681 · 17,362 (double) · 26,043 · 34,724 · 43,405 · 52,086 · 60,767 · 69,448 · 78,129 · 86,810

Sums & aliquot sequence

As a sum of two squares: 20² + 91²

As consecutive integers: 4,340 + 4,341

Continued fraction of √n

√8,681 = [93; (5, 1, 4, 2, 26, 5, 1, 36, 2, 3, 3, 4, 2, 1, 4, 1, 1, 1, 2, 1, 2, 7, 11, 1, …)]

Representations

In words: eight thousand six hundred eighty-one
Ordinal: 8681st
Binary: 10000111101001
Octal: 20751
Hexadecimal: 0x21E9
Base64: Iek=
One's complement: 56,854 (16-bit)
Scientific notation: 8.681 × 10³
As a duration: 8,681 s = 2 hours, 24 minutes, 41 seconds

In other bases

ternary (3) 102220112

quaternary (4) 2013221

quinary (5) 234211

senary (6) 104105

septenary (7) 34211

nonary (9) 12815

undecimal (11) 6582

duodecimal (12) 5035

tridecimal (13) 3c4a

tetradecimal (14) 3241

pentadecimal (15) 288b

As an angle

8,681° = 24 × 360° + 41°

41° ≈ 0.716 rad

Compass bearing: NE (northeast)

Why does a circle have 360 degrees? →

Historical numeral systems

Babylonian (base 60): 𒁹𒁹 𒌋𒌋𒁹𒁹𒁹𒁹 𒌋𒌋𒌋𒌋𒁹
Egyptian hieroglyphic: 𓆼𓆼𓆼𓆼𓆼𓆼𓆼𓆼𓍢𓍢𓍢𓍢𓍢𓍢𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓏺
Greek (Milesian): ͵ηχπαʹ
Mayan (base 20): 𝋡·𝋡·𝋮·𝋡
Chinese: 八千六百八十一
Chinese (financial): 捌仟陸佰捌拾壹

In other modern scripts

Eastern Arabic ٨٦٨١ Devanagari ८६८१ Bengali ৮৬৮১ Tamil ௮௬௮௧ Thai ๘๖๘๑ Tibetan ༨༦༨༡ Khmer ៨៦៨១ Lao ໘໖໘໑ Burmese ၈၆၈၁

Digit at this position in famous constants

π — Pi (π): Digit 8,681 = 9
e — Euler's number (e): Digit 8,681 = 3
φ — Golden ratio (φ): Digit 8,681 = 4
√2 — Pythagoras's (√2): Digit 8,681 = 7
ln 2 — Natural log of 2: Digit 8,681 = 8
γ — Euler-Mascheroni (γ): Digit 8,681 = 1

Also seen as

Prime neighborhood

Adjacent primes:

Previous prime: 8,677 (gap of 4)
Next prime: 8,689 (gap of 8)

Pair status: cousin with 8677.

Unicode codepoint

⇩

Downwards White Arrow

U+21E9

Other symbol (So)

UTF-8 encoding: E2 87 A9 (3 bytes).

Lookup U+21E9 on Compart ↗ Lookup on FileFormat.Info ↗

Hex color

#0021E9

RGB(0, 33, 233)

IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.33.233.

Address: 0.0.33.233
Class: reserved
IPv4-mapped IPv6: ::ffff:0.0.33.233

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

Musical pitch

Heard as a frequency, 8,681 Hz is closest to:

Concert pitch (A4 = 440 Hz): C♯9 (8869.8 Hz, -37¢)
Scientific pitch (C4 = 256 Hz): C♯9 (8679.1 Hz, exact)
Baroque pitch (A4 = 415 Hz): D9 (8863.3 Hz, -36¢)

Position in π

The digit sequence 8681 first appears in π at position 19,219 of the decimal expansion (the 19,219ordinal-suffix:th 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 8681 on Pi Search ↗