524
E524 is sodium hydroxide.
- Even
- Composite
Where 524 fits
Why 524 is special
Caustic soda appears on ingredient lists because it is used to treat olives and to give pretzels their crust, which surprises most readers.
Factors & digit properties
- Divisors (6)
- 1, 2, 4, 131, 262, 524
- Prime factorisation
- 2^2 × 131
- Digit sum
- 11
- Digital root
- 2
Representations
- Decimal
- 524
- Scientific notation
- 5.240 × 10^2
Roman numerals
D X X I V
DXXIV uses the subtractive pair IV: one before five — five minus one.
Binary
1 0 0 0 0 0 1 1 0 0
1 × 512 + 0 × 256 + 0 × 128 + 0 × 64 + 0 × 32 + 0 × 16 + 1 × 8 + 1 × 4 + 0 × 2 + 0 × 1 = 524
Octal
1 0 1 4
1 × 512 + 0 × 64 + 1 × 8 + 4 × 1 = 524
Hexadecimal
2 0 c
2 × 256 + 0 × 16 + c × 1 = 524
Read as powers of two: 512 + 8 + 4 = 524.
In historical numeral systems
Egyptian
5 coils of rope, 2 hobbles, 4 strokes
5 × 100 + 2 × 10 + 4 × 1 = 524. The signs are simply repeated and added; where they sit on the line is a matter of layout, not value.
Babylonian
8 vertical wedges (sixties place), 4 corner wedges + 4 vertical wedges (units place)
8 × 60 + 44 = 524. Places are separated by a space on the tablet, with the higher place written first.
Greek (Ionic)
phi, then kappa, then delta, marked as a numeral
phi-kappa-delta + keraia
phi + kappa + 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 qof, then kaf, then dalet
tav-qof-kaf-dalet
tav (400) + qof (100) + kaf (20) + dalet (4) = 524, 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
- Deficient number
Related numbers & connections
Both are additives most readers would not expect to see on a food label at all.
View 570 →Numbers Around Us
- appears alongside570
why?
Strength 0.50, confidence "high".
Everyday life
E524 sodium hydroxide is used as an acidity regulator, in olive curing and in the alkaline bath that produces the characteristic crust and flavour of pretzels.
DocumentedEveryday lifeGeography: European Union and states adopting the E number systemPeriod: 1962–
Common questions
Is 524 a prime number?
No, 524 is not prime.
What are the factors of 524?
The factors of 524 are 1, 2, 4, 131, 262, 524.
What is 524 in Roman numerals?
524 in Roman numerals is DXXIV. IV is subtractive: one before five — five minus one. Written additively it would be DXXIIII, 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