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21,648

21,648 is a composite number, even.

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.).
Abundant Number Odious Number Pernicious Number Practical Number Recamán's Sequence Semiperfect Number

Properties

Parity
Even
Digit count
5
Digit sum
21
Digit product
384
Digital root
3
Palindrome
No
Bit width
15 bits
Reversed
84,612
Recamán's sequence
a(40,543) = 21,648
Square (n²)
468,635,904
Cube (n³)
10,145,030,049,792
Divisor count
40
σ(n) — sum of divisors
62,496
φ(n) — Euler's totient
6,400
Sum of prime factors
63

Primality

Prime factorization: 2 4 × 3 × 11 × 41

Nearest primes: 21,647 (−1) · 21,649 (+1)

Divisors & multiples

All divisors (40)
1 · 2 · 3 · 4 · 6 · 8 · 11 · 12 · 16 · 22 · 24 · 33 · 41 · 44 · 48 · 66 · 82 · 88 · 123 · 132 · 164 · 176 · 246 · 264 · 328 · 451 · 492 · 528 · 656 · 902 · 984 · 1353 · 1804 · 1968 · 2706 · 3608 · 5412 · 7216 · 10824 (half) · 21648
Aliquot sum (sum of proper divisors): 40,848
Factor pairs (a × b = 21,648)
1 × 21648
2 × 10824
3 × 7216
4 × 5412
6 × 3608
8 × 2706
11 × 1968
12 × 1804
16 × 1353
22 × 984
24 × 902
33 × 656
41 × 528
44 × 492
48 × 451
66 × 328
82 × 264
88 × 246
123 × 176
132 × 164
First multiples
21,648 · 43,296 (double) · 64,944 · 86,592 · 108,240 · 129,888 · 151,536 · 173,184 · 194,832 · 216,480

Sums & aliquot sequence

As consecutive integers: 7,215 + 7,216 + 7,217 1,963 + 1,964 + … + 1,973 661 + 662 + … + 692 640 + 641 + … + 672
Aliquot sequence: 21,648 40,848 72,240 189,648 355,952 333,736 340,364 255,280 338,432 338,794 177,914 113,254 66,674 44,134 22,070 17,674 8,840 — unresolved within range

Representations

In words
twenty-one thousand six hundred forty-eight
Ordinal
21648th
Binary
101010010010000
Octal
52220
Hexadecimal
0x5490
Base64
VJA=
One's complement
43,887 (16-bit)
In other bases
ternary (3) 1002200210
quaternary (4) 11102100
quinary (5) 1143043
senary (6) 244120
septenary (7) 120054
nonary (9) 32623
undecimal (11) 152a0
duodecimal (12) 10640
tridecimal (13) 9b13
tetradecimal (14) 7c64
pentadecimal (15) 6633

Historical numeral systems

Babylonian (base 60)
𒁹𒁹𒁹𒁹𒁹𒁹 · 𒌋𒌋𒌋𒌋𒁹𒁹𒁹𒁹𒁹𒁹𒁹𒁹
Egyptian hieroglyphic
𓂍𓂍𓆼𓍢𓍢𓍢𓍢𓍢𓍢𓎆𓎆𓎆𓎆𓏺𓏺𓏺𓏺𓏺𓏺𓏺𓏺
Greek (Milesian)
͵καχμηʹ
Mayan (base 20)
𝋢·𝋮·𝋢·𝋨
Chinese
二萬一千六百四十八
Chinese (financial)
貳萬壹仟陸佰肆拾捌
In other modern scripts
Eastern Arabic ٢١٦٤٨ Devanagari २१६४८ Bengali ২১৬৪৮ Tamil ௨௧௬௪௮ Thai ๒๑๖๔๘ Tibetan ༢༡༦༤༨ Khmer ២១៦៤៨ Lao ໒໑໖໔໘ Burmese ၂၁၆၄၈

Digit at this position in famous constants

π — Pi (π)
Digit 21,648 = 0
e — Euler's number (e)
Digit 21,648 = 9
φ — Golden ratio (φ)
Digit 21,648 = 6
√2 — Pythagoras's (√2)
Digit 21,648 = 6
ln 2 — Natural log of 2
Digit 21,648 = 3
γ — Euler-Mascheroni (γ)
Digit 21,648 = 8

Also seen as

Goldbach decomposition

Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 21648, here are decompositions:

  • 31 + 21617 = 21648
  • 37 + 21611 = 21648
  • 47 + 21601 = 21648
  • 59 + 21589 = 21648
  • 61 + 21587 = 21648
  • 71 + 21577 = 21648
  • 79 + 21569 = 21648
  • 89 + 21559 = 21648

Showing the first eight; more decompositions exist.

Unicode codepoint
CJK Unified Ideograph-5490
U+5490
Other letter (Lo)

UTF-8 encoding: E5 92 90 (3 bytes).

Hex color
#005490
RGB(0, 84, 144)
IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.84.144.

Address
0.0.84.144
Class
reserved
IPv4-mapped IPv6
::ffff:0.0.84.144

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

Position in π

The digit sequence 21648 first appears in π at position 180,622 of the decimal expansion (the 180,622ordinal-suffix:nd 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.