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6,561

6,561 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.).
Deficient Number Evil Number Perfect Square Powerful Number Recamán's Sequence

Properties

Parity
Odd
Digit count
4
Digit sum
18
Digit product
180
Digital root
9
Palindrome
No
Bit width
13 bits
Reversed
1,656
Recamán's sequence
a(53,277) = 6,561
Square (n²)
43,046,721
Cube (n³)
282,429,536,481
Square root (√n)
81
Divisor count
9
σ(n) — sum of divisors
9,841
φ(n) — Euler's totient
4,374
Sum of prime factors
24

Primality

Prime factorization: 3 8

Nearest primes: 6,553 (−8) · 6,563 (+2)

Divisors & multiples

All divisors (9)
1 · 3 · 9 · 27 · 81 · 243 · 729 · 2187 · 6561
Aliquot sum (sum of proper divisors): 3,280
Factor pairs (a × b = 6,561)
1 × 6561
3 × 2187
9 × 729
27 × 243
81 × 81
First multiples
6,561 · 13,122 (double) · 19,683 · 26,244 · 32,805 · 39,366 · 45,927 · 52,488 · 59,049 · 65,610

Sums & aliquot sequence

As a sum of two squares: 0² + 81²
As consecutive integers: 3,280 + 3,281 2,186 + 2,187 + 2,188 1,091 + 1,092 + 1,093 + 1,094 + 1,095 + 1,096 725 + 726 + … + 733
Aliquot sequence: 6,561 3,280 4,532 4,204 3,160 4,040 5,140 5,696 5,734 3,194 1,600 2,337 1,023 513 287 49 8 — unresolved within range

Representations

In words
six thousand five hundred sixty-one
Ordinal
6561st
Binary
1100110100001
Octal
14641
Hexadecimal
0x19A1
Base64
GaE=
One's complement
58,974 (16-bit)
In other bases
ternary (3) 100000000
quaternary (4) 1212201
quinary (5) 202221
senary (6) 50213
septenary (7) 25062
nonary (9) 10000
undecimal (11) 4a25
duodecimal (12) 3969
tridecimal (13) 2ca9
tetradecimal (14) 2569
pentadecimal (15) 1e26

Historical numeral systems

Babylonian (base 60)
𒁹 𒌋𒌋𒌋𒌋𒁹𒁹𒁹𒁹𒁹𒁹𒁹𒁹𒁹 𒌋𒌋𒁹
Egyptian hieroglyphic
𓆼𓆼𓆼𓆼𓆼𓆼𓍢𓍢𓍢𓍢𓍢𓎆𓎆𓎆𓎆𓎆𓎆𓏺
Greek (Milesian)
͵ϛφξαʹ
Mayan (base 20)
𝋰·𝋨·𝋡
Chinese
六千五百六十一
Chinese (financial)
陸仟伍佰陸拾壹
In other modern scripts
Eastern Arabic ٦٥٦١ Devanagari ६५६१ Bengali ৬৫৬১ Tamil ௬௫௬௧ Thai ๖๕๖๑ Tibetan ༦༥༦༡ Khmer ៦៥៦១ Lao ໖໕໖໑ Burmese ၆၅၆၁

Digit at this position in famous constants

π — Pi (π)
Digit 6,561 = 5
e — Euler's number (e)
Digit 6,561 = 7
φ — Golden ratio (φ)
Digit 6,561 = 2
√2 — Pythagoras's (√2)
Digit 6,561 = 7
ln 2 — Natural log of 2
Digit 6,561 = 0
γ — Euler-Mascheroni (γ)
Digit 6,561 = 4

Also seen as

Unicode codepoint
New Tai Lue Letter High Da
U+19A1
Other letter (Lo)

UTF-8 encoding: E1 A6 A1 (3 bytes).

Hex color
#0019A1
RGB(0, 25, 161)
IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.25.161.

Address
0.0.25.161
Class
reserved
IPv4-mapped IPv6
::ffff:0.0.25.161

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

Position in π

The digit sequence 6561 first appears in π at position 3,798 of the decimal expansion (the 3,798ordinal-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.