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6,440

6,440 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 Arithmetic Number Happy Number Harshad / Niven Odious Number Pernicious Number Practical Number Recamán's Sequence Semiperfect Number

Properties

Parity
Even
Digit count
4
Digit sum
14
Digit product
0
Digital root
5
Palindrome
No
Bit width
13 bits
Reversed
446
Recamán's sequence
a(27,020) = 6,440
Square (n²)
41,473,600
Cube (n³)
267,089,984,000
Divisor count
32
σ(n) — sum of divisors
17,280
φ(n) — Euler's totient
2,112
Sum of prime factors
41

Primality

Prime factorization: 2 3 × 5 × 7 × 23

Nearest primes: 6,427 (−13) · 6,449 (+9)

Divisors & multiples

All divisors (32)
1 · 2 · 4 · 5 · 7 · 8 · 10 · 14 · 20 · 23 · 28 · 35 · 40 · 46 · 56 · 70 · 92 · 115 · 140 · 161 · 184 · 230 · 280 · 322 · 460 · 644 · 805 · 920 · 1288 · 1610 · 3220 (half) · 6440
Aliquot sum (sum of proper divisors): 10,840
Factor pairs (a × b = 6,440)
1 × 6440
2 × 3220
4 × 1610
5 × 1288
7 × 920
8 × 805
10 × 644
14 × 460
20 × 322
23 × 280
28 × 230
35 × 184
40 × 161
46 × 140
56 × 115
70 × 92
First multiples
6,440 · 12,880 (double) · 19,320 · 25,760 · 32,200 · 38,640 · 45,080 · 51,520 · 57,960 · 64,400

Sums & aliquot sequence

As consecutive integers: 1,286 + 1,287 + 1,288 + 1,289 + 1,290 917 + 918 + … + 923 395 + 396 + … + 410 269 + 270 + … + 291
Aliquot sequence: 6,440 10,840 13,640 20,920 26,240 38,020 41,864 36,646 19,298 9,652 8,268 12,900 25,292 18,976 18,446 10,498 5,882 — unresolved within range

Representations

In words
six thousand four hundred forty
Ordinal
6440th
Binary
1100100101000
Octal
14450
Hexadecimal
0x1928
Base64
GSg=
One's complement
59,095 (16-bit)
In other bases
ternary (3) 22211112
quaternary (4) 1210220
quinary (5) 201230
senary (6) 45452
septenary (7) 24530
nonary (9) 8745
undecimal (11) 4925
duodecimal (12) 3888
tridecimal (13) 2c15
tetradecimal (14) 24c0
pentadecimal (15) 1d95

Historical numeral systems

Babylonian (base 60)
𒁹 𒌋𒌋𒌋𒌋𒁹𒁹𒁹𒁹𒁹𒁹𒁹 𒌋𒌋
Egyptian hieroglyphic
𓆼𓆼𓆼𓆼𓆼𓆼𓍢𓍢𓍢𓍢𓎆𓎆𓎆𓎆
Greek (Milesian)
͵ϛυμʹ
Mayan (base 20)
𝋰·𝋢·𝋠
Chinese
六千四百四十
Chinese (financial)
陸仟肆佰肆拾
In other modern scripts
Eastern Arabic ٦٤٤٠ Devanagari ६४४० Bengali ৬৪৪০ Tamil ௬௪௪௦ Thai ๖๔๔๐ Tibetan ༦༤༤༠ Khmer ៦៤៤០ Lao ໖໔໔໐ Burmese ၆၄၄၀

Digit at this position in famous constants

π — Pi (π)
Digit 6,440 = 0
e — Euler's number (e)
Digit 6,440 = 6
φ — Golden ratio (φ)
Digit 6,440 = 8
√2 — Pythagoras's (√2)
Digit 6,440 = 2
ln 2 — Natural log of 2
Digit 6,440 = 0
γ — Euler-Mascheroni (γ)
Digit 6,440 = 0

Also seen as

Goldbach decomposition

Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 6440, here are decompositions:

  • 13 + 6427 = 6440
  • 19 + 6421 = 6440
  • 43 + 6397 = 6440
  • 61 + 6379 = 6440
  • 67 + 6373 = 6440
  • 73 + 6367 = 6440
  • 79 + 6361 = 6440
  • 97 + 6343 = 6440

Showing the first eight; more decompositions exist.

Unicode codepoint
Limbu Vowel Sign O
U+1928
Non-spacing mark (Mn)

UTF-8 encoding: E1 A4 A8 (3 bytes).

Hex color
#001928
RGB(0, 25, 40)
IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.25.40.

Address
0.0.25.40
Class
reserved
IPv4-mapped IPv6
::ffff:0.0.25.40

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

Position in π

The digit sequence 6440 first appears in π at position 17,846 of the decimal expansion (the 17,846ordinal-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.