Live analysis

2,661

2,661 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.).

2,661 (two thousand six hundred sixty-one) is an odd 4-digit number. It is a composite number with 4 divisors, and factors as 3 × 887. Written other ways, in Roman numerals it is MMDCLXI and in binary, 101001100101.

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

Interestingness

★ ★ ★ ★ ☆

7 notable facts · grade B

2,649 2,650 2,651 2,652 2,653 2,654 2,655 2,656 2,657 2,658 2,659 2,660 2,661 2,662 2,663 2,664 2,665 2,666 2,667 2,668 2,669 2,670 2,671 2,672 2,673

less more

Properties

Parity: Odd
Digit count: 4
Digit sum: 15
Digit product: 72
Digital root: 6
Palindrome: No
Bit width: 12 bits
Reversed: 1,662
Recamán's sequence: a(7,310) = 2,661
Square (n²): 7,080,921
Cube (n³): 18,842,330,781
Divisor count: 4
σ(n) — sum of divisors: 3,552
φ(n) — Euler's totient: 1,772
Sum of prime factors: 890

Primality

Prime factorization: 3 × 887

Nearest primes: 2,659 (−2) · 2,663 (+2)

Divisors & multiples

All divisors (4)

1 · 3 · 887 · 2661

Aliquot sum (sum of proper divisors): 891

Factor pairs (a × b = 2,661)

1 × 2661

3 × 887

First multiples

2,661 · 5,322 (double) · 7,983 · 10,644 · 13,305 · 15,966 · 18,627 · 21,288 · 23,949 · 26,610

Sums & aliquot sequence

As consecutive integers: 1,330 + 1,331 886 + 887 + 888 441 + 442 + 443 + 444 + 445 + 446

Aliquot sequence: 2,661 → 891 → 561 → 303 → 105 → 87 → 33 → 15 → 9 → 4 → 3 → 1 → 0 — terminates at zero

Continued fraction of √n

√2,661 = [51; (1, 1, 2, 2, 4, 14, 1, 1, 20, 8, 1, 1, 4, 1, 1, 1, 2, 3, 3, 3, 1, 4, 1, 1, …)]

Representations

In words: two thousand six hundred sixty-one
Ordinal: 2661st
Roman numeral: MMDCLXI
Binary: 101001100101
Octal: 5145
Hexadecimal: 0xA65
Base64: CmU=
One's complement: 62,874 (16-bit)
Scientific notation: 2.661 × 10³
As a duration: 2,661 s = 44 minutes, 21 seconds

In other bases

ternary (3) 10122120

quaternary (4) 221211

quinary (5) 41121

senary (6) 20153

septenary (7) 10521

nonary (9) 3576

undecimal (11) 1aaa

duodecimal (12) 1659

tridecimal (13) 1299

tetradecimal (14) d81

pentadecimal (15) bc6

Palindromic in base 2

As an angle

2,661° = 7 × 360° + 141°

141° ≈ 2.461 rad

Compass bearing: SE (southeast)

Why does a circle have 360 degrees? →

Historical numeral systems

Babylonian (base 60): 𒌋𒌋𒌋𒌋𒁹𒁹𒁹𒁹 𒌋𒌋𒁹
Egyptian hieroglyphic: 𓆼𓆼𓍢𓍢𓍢𓍢𓍢𓍢𓎆𓎆𓎆𓎆𓎆𓎆𓏺
Greek (Milesian): ͵βχξαʹ
Mayan (base 20): 𝋦·𝋭·𝋡
Chinese: 二千六百六十一
Chinese (financial): 貳仟陸佰陸拾壹

In other modern scripts

Eastern Arabic ٢٦٦١ Devanagari २६६१ Bengali ২৬৬১ Tamil ௨௬௬௧ Thai ๒๖๖๑ Tibetan ༢༦༦༡ Khmer ២៦៦១ Lao ໒໖໖໑ Burmese ၂၆၆၁

Digit at this position in famous constants

π — Pi (π): Digit 2,661 = 5
e — Euler's number (e): Digit 2,661 = 5
φ — Golden ratio (φ): Digit 2,661 = 1
√2 — Pythagoras's (√2): Digit 2,661 = 1
ln 2 — Natural log of 2: Digit 2,661 = 6
γ — Euler-Mascheroni (γ): Digit 2,661 = 6

Also seen as

Hex color

#000A65

RGB(0, 10, 101)

IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.10.101.

Address: 0.0.10.101
Class: reserved
IPv4-mapped IPv6: ::ffff:0.0.10.101

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

Musical pitch

Heard as a frequency, 2,661 Hz is closest to:

Concert pitch (A4 = 440 Hz): E7 (2637 Hz, +16¢)
Scientific pitch (C4 = 256 Hz): F7 (2733.8 Hz, -47¢ — about midway to E7)
Baroque pitch (A4 = 415 Hz): F7 (2635.1 Hz, +17¢)

Position in π

The digit sequence 2661 first appears in π at position 20,666 of the decimal expansion (the 20,666ordinal-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 2661 on Pi Search ↗