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Number

6,661

6,661 is a prime, odd.

Arithmetic Number Chen Prime Deficient Number Flippable Happy Number Odious Number Pernicious Number Prime Pythagorean Prime Recamán's Sequence Squarefree Twin Prime

Properties

Parity
Odd
Digit count
4
Digit sum
19
Digit product
216
Digital root
1
Palindrome
No
Bit width
13 bits
Reversed
1,666
Flips to (rotate 180°)
1,999
Recamán's sequence
a(11,885) = 6,661
Square (n²)
44,368,921
Cube (n³)
295,541,382,781
Divisor count
2
σ(n) — sum of divisors
6,662
φ(n) — Euler's totient
6,660

Primality

6,661 is prime. It has exactly two divisors: 1 and itself.

Divisors & multiples

All divisors (2)
1 · 6661
Aliquot sum (sum of proper divisors): 1
Factor pairs (a × b = 6,661)
1 × 6661
First multiples
6,661 · 13,322 (double) · 19,983 · 26,644 · 33,305 · 39,966 · 46,627 · 53,288 · 59,949 · 66,610

Sums & aliquot sequence

As a sum of two squares: 10² + 81²
As consecutive integers: 3,330 + 3,331

Representations

In words
six thousand six hundred sixty-one
Ordinal
6661st
Binary
1101000000101
Octal
15005
Hexadecimal
0x1A05
Base64
GgU=
One's complement
58,874 (16-bit)
In other bases
ternary (3) 100010201
quaternary (4) 1220011
quinary (5) 203121
senary (6) 50501
septenary (7) 25264
nonary (9) 10121
undecimal (11) 5006
duodecimal (12) 3a31
tridecimal (13) 3055
tetradecimal (14) 25db
pentadecimal (15) 1e91

Historical numeral systems

Babylonian (base 60)
𒁹 𒌋𒌋𒌋𒌋𒌋𒁹 𒁹
Egyptian hieroglyphic
𓆼𓆼𓆼𓆼𓆼𓆼𓍢𓍢𓍢𓍢𓍢𓍢𓎆𓎆𓎆𓎆𓎆𓎆𓏺
Greek (Milesian)
͵ϛχξαʹ
Mayan (base 20)
𝋰·𝋭·𝋡
Chinese
六千六百六十一
Chinese (financial)
陸仟陸佰陸拾壹
In other modern scripts
Eastern Arabic ٦٦٦١ Devanagari ६६६१ Bengali ৬৬৬১ Tamil ௬௬௬௧ Thai ๖๖๖๑ Tibetan ༦༦༦༡ Khmer ៦៦៦១ Lao ໖໖໖໑ Burmese ၆၆၆၁

Digit at this position in famous constants

π — Pi (π)
Digit 6,661 = 3
e — Euler's number (e)
Digit 6,661 = 9
φ — Golden ratio (φ)
Digit 6,661 = 7
√2 — Pythagoras's (√2)
Digit 6,661 = 0
ln 2 — Natural log of 2
Digit 6,661 = 4
γ — Euler-Mascheroni (γ)
Digit 6,661 = 9

Also seen as

Prime neighborhood

Adjacent primes:

  • Previous prime: 6,659 (gap of 2)
  • Next prime: 6,673 (gap of 12)

Pair status: twin with 6659.

Unicode codepoint
Buginese Letter Ba
U+1A05
Other letter (Lo)

UTF-8 encoding: E1 A8 85 (3 bytes).

Hex color
#001A05
RGB(0, 26, 5)
IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.26.5.

Address
0.0.26.5
Class
reserved
IPv4-mapped IPv6
::ffff:0.0.26.5

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

Position in π

The digit sequence 6661 first appears in π at position 13,594 of the decimal expansion (the 13,594ordinal-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.