number.wiki
Number

688

688 is a composite number, even, a calendar year.

Deficient Number Year

Properties

Parity
Even
Digit count
3
Digit sum
22
Digital root
4
Palindrome
No
Divisor count
10
σ(n) — sum of divisors
1,364

Primality

Prime factorization: 2 4 × 43

Divisors & multiples

All divisors (10)
1 · 2 · 4 · 8 · 16 · 43 · 86 · 172 · 344 · 688
Aliquot sum (sum of proper divisors): 676
Factor pairs (a × b = 688)
1 × 688
2 × 344
4 × 172
8 × 86
16 × 43
First multiples
688 · 1,376 · 2,064 · 2,752 · 3,440 · 4,128 · 4,816 · 5,504 · 6,192 · 6,880

Representations

In words
six hundred eighty-eight
Ordinal
688th
Roman numeral
DCLXXXVIII
Binary
1010110000
Octal
1260
Hexadecimal
2B0

Also seen as

Goldbach decomposition

Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 688, here are decompositions:

  • 5 + 683 = 688
  • 11 + 677 = 688
  • 29 + 659 = 688
  • 41 + 647 = 688
  • 47 + 641 = 688
  • 71 + 617 = 688
  • 89 + 599 = 688
  • 101 + 587 = 688

Showing the first eight; more decompositions exist.

Unicode codepoint
ʰ
U+02B0
Modifier letter (Lm)

UTF-8 encoding: CA B0 (2 bytes).

Lookup U+02B0 on Compart ↗ Lookup on FileFormat.Info ↗
Hex color
#0002B0
RGB(0, 2, 176)
IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.2.176.