684
+684 is the international calling code for American Samoa.
- Even
- Composite
Where 684 fits
Why 684 is special
American Samoa is a US territory whose people are US nationals but not automatically US citizens — the only place with that status.
Factors & digit properties
- Divisors (18)
- 1, 2, 3, 4, 6, 9, 12, 18, 19, 36, 38, 57, 76, 114, 171, 228, 342, 684
- Prime factorisation
- 2^2 × 3^2 × 19
- Digit sum
- 18
- Digital root
- 9
Representations
- Decimal
- 684
- Scientific notation
- 6.840 × 10^2
Roman numerals
D C L X X X I V
DCLXXXIV uses the subtractive pair IV: one before five — five minus one.
Binary
1 0 1 0 1 0 1 1 0 0
1 × 512 + 0 × 256 + 1 × 128 + 0 × 64 + 1 × 32 + 0 × 16 + 1 × 8 + 1 × 4 + 0 × 2 + 0 × 1 = 684
Octal
1 2 5 4
1 × 512 + 2 × 64 + 5 × 8 + 4 × 1 = 684
Hexadecimal
2 a c
2 × 256 + a × 16 + c × 1 = 684
Read as powers of two: 512 + 128 + 32 + 8 + 4 = 684.
In historical numeral systems
Egyptian
6 coils of rope, 8 hobbles, 4 strokes
6 × 100 + 8 × 10 + 4 × 1 = 684. The signs are simply repeated and added; where they sit on the line is a matter of layout, not value.
Babylonian
1 corner wedge + 1 vertical wedge (sixties place), 2 corner wedges + 4 vertical wedges (units place)
11 × 60 + 24 = 684. Places are separated by a space on the tablet, with the higher place written first.
Greek (Ionic)
chi, then pi, then delta, marked as a numeral
chi-pi-delta + keraia
chi + pi + delta written in descending order and added — the letters carry their values wherever they stand, so this is addition, not place value.
Hebrew numerals
tav, then resh, then pe, then dalet
tav-resh-pe-dalet
tav (400) + resh (200) + pe (80) + dalet (4) = 684, written in descending order.
Systems that simply cannot reach this value are left out. Where a script needs a font most readers do not have, the reading is given instead of the glyphs — see number systems for each system in full.
Other mathematical patterns
- Abundant number
- Harshad (Niven) number
Related numbers & connections
American Samoa and Samoa are the two halves of the same archipelago under different sovereignties. American Samoans are US nationals but not automatically US citizens.
View 685 →Other connections
- is associated with685
why?
Strength 0.50, confidence "high".
Geography
+684 reaches American Samoa, whose residents are US nationals rather than citizens by birth, a distinction unique among US territories.
DocumentedGeographyGeography: American Samoa
Common questions
Is 684 a prime number?
No, 684 is not prime.
What are the factors of 684?
The factors of 684 are 1, 2, 3, 4, 6, 9, 12, 18, 19, 36, 38, 57, 76, 114, 171, 228, 342, 684.
What is 684 in Roman numerals?
684 in Roman numerals is DCLXXXIV. IV is subtractive: one before five — five minus one. Written additively it would be DCLXXXIIII, which Roman inscriptions used freely — the strict subtractive form is a later convention.
About this page's data
Mathematical facts:computed directly from the number's value — nothing to source or verify externally.
Contextual records: 1 reviewer-confirmed record, sourced and reviewed before publication.
Last reviewed: 15 July 2026