Number

3,581

3,581 is a prime, odd.

3,581 (three thousand five hundred eighty-one) is an odd 4-digit number. It is a prime number — divisible only by 1 and itself. Written other ways, in Roman numerals it is MMMDLXXXI and in binary, 110111111101.

Arithmetic Number Chen Prime Cube-Free Deficient Number Evil Number Prime Pythagorean Prime Recamán's Sequence Squarefree Twin Prime

Interestingness

★ ★ ★ ★ ★

8 notable facts · grade A

3,569 3,570 3,571 3,572 3,573 3,574 3,575 3,576 3,577 3,578 3,579 3,580 3,581 3,582 3,583 3,584 3,585 3,586 3,587 3,588 3,589 3,590 3,591 3,592 3,593

less more

Properties

Parity: Odd
Digit count: 4
Digit sum: 17
Digit product: 120
Digital root: 8
Palindrome: No
Bit width: 12 bits
Reversed: 1,853
Recamán's sequence: a(14,729) = 3,581
Square (n²): 12,823,561
Cube (n³): 45,921,171,941
Divisor count: 2
σ(n) — sum of divisors: 3,582
φ(n) — Euler's totient: 3,580

Primality

3,581 is prime. It has exactly two divisors: 1 and itself.

Divisors & multiples

All divisors (2)

1 · 3581

Aliquot sum (sum of proper divisors): 1

Factor pairs (a × b = 3,581)

1 × 3581

First multiples

3,581 · 7,162 (double) · 10,743 · 14,324 · 17,905 · 21,486 · 25,067 · 28,648 · 32,229 · 35,810

Sums & aliquot sequence

As a sum of two squares: 10² + 59²

As consecutive integers: 1,790 + 1,791

Continued fraction of √n

√3,581 = [59; (1, 5, 3, 3, 1, 23, 5, 1, 16, 3, 1, 4, 29, 1, 2, 2, 4, 1, 3, 2, 5, 1, 1, 5, …)]

Period length 45 — the block in parentheses repeats forever.

Representations

In words: three thousand five hundred eighty-one
Ordinal: 3581st
Roman numeral: MMMDLXXXI
Binary: 110111111101
Octal: 6775
Hexadecimal: 0xDFD
Base64: Df0=
One's complement: 61,954 (16-bit)
Scientific notation: 3.581 × 10³
As a duration: 3,581 s = 59 minutes, 41 seconds

In other bases

ternary (3) 11220122

quaternary (4) 313331

quinary (5) 103311

senary (6) 24325

septenary (7) 13304

nonary (9) 4818

undecimal (11) 2766

duodecimal (12) 20a5

tridecimal (13) 1826

tetradecimal (14) 143b

pentadecimal (15) 10db

Palindromic in base 16

As an angle

3,581° = 9 × 360° + 341°

341° ≈ 5.952 rad

Compass bearing: NNW (north-northwest)

Why does a circle have 360 degrees? →

Historical numeral systems

Babylonian (base 60): 𒌋𒌋𒌋𒌋𒌋𒁹𒁹𒁹𒁹𒁹𒁹𒁹𒁹𒁹 𒌋𒌋𒌋𒌋𒁹
Egyptian hieroglyphic: 𓆼𓆼𓆼𓍢𓍢𓍢𓍢𓍢𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓏺
Greek (Milesian): ͵γφπαʹ
Mayan (base 20): 𝋨·𝋳·𝋡
Chinese: 三千五百八十一
Chinese (financial): 參仟伍佰捌拾壹

In other modern scripts

Eastern Arabic ٣٥٨١ Devanagari ३५८१ Bengali ৩৫৮১ Tamil ௩௫௮௧ Thai ๓๕๘๑ Tibetan ༣༥༨༡ Khmer ៣៥៨១ Lao ໓໕໘໑ Burmese ၃၅၈၁

Digit at this position in famous constants

π — Pi (π): Digit 3,581 = 5
e — Euler's number (e): Digit 3,581 = 9
φ — Golden ratio (φ): Digit 3,581 = 1
√2 — Pythagoras's (√2): Digit 3,581 = 8
ln 2 — Natural log of 2: Digit 3,581 = 7
γ — Euler-Mascheroni (γ): Digit 3,581 = 6

Also seen as

Prime neighborhood

Adjacent primes:

Previous prime: 3,571 (gap of 10)
Next prime: 3,583 (gap of 2)

Pair status: twin with 3583.

Hex color

#000DFD

RGB(0, 13, 253)

IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.13.253.

Address: 0.0.13.253
Class: reserved
IPv4-mapped IPv6: ::ffff:0.0.13.253

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

Musical pitch

Heard as a frequency, 3,581 Hz is closest to:

Concert pitch (A4 = 440 Hz): A7 (3520 Hz, +30¢)
Scientific pitch (C4 = 256 Hz): A♯7 (3649.1 Hz, -33¢)
Baroque pitch (A4 = 415 Hz): A♯7 (3517.4 Hz, +31¢)

Position in π

The digit sequence 3581 first appears in π at position 7,274 of the decimal expansion (the 7,274ordinal-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 3581 on Pi Search ↗