34
34 is the 9th Fibonacci number, and the atomic number of selenium.
Where 34 fits
Why 34 is special
34's clean membership in the Fibonacci sequence (1, 1, 2, 3, 5, 8, 13, 21, 34) is its most notable mathematical property.
Same number, different meanings
How 34 is understood across different contexts — never implying one meaning because of another.
- Mathematics
34's clean membership in the Fibonacci sequence (1, 1, 2, 3, 5, 8, 13, 21, 34) is its most notable mathematical property.
- Technology & computing
Xerography — the process behind every photocopier and laser printer — worked commercially because of element 34. A selenium-coated drum holds a static charge in the dark and loses it where light falls, so a projected image becomes a pattern of charge that toner sticks to. Selenium drums were standard from the first Xerox machines until organic photoconductors displaced them.
- Everyday life
Element 34 is in most medicated anti-dandruff shampoos: selenium sulfide slows the skin-cell turnover and fungal growth behind seborrhoeic dermatitis. It is one of the few places a trace element from the middle of the periodic table appears on a supermarket shelf by name.
- Science
34 is the atomic number of selenium, an essential trace mineral.
34 is part of
Factors & digit properties
- Divisors (4)
- 1, 2, 17, 34
- Prime factorisation
- 2 × 17
- Digit sum
- 7
- Digital root
- 7
Representations
- Decimal
- 34
- Scientific notation
- 3.400 × 10^1
Roman numerals
X X X I V
XXXIV uses the subtractive pair IV: one before five — five minus one.
Binary
1 0 0 0 1 0
1 × 32 + 0 × 16 + 0 × 8 + 0 × 4 + 1 × 2 + 0 × 1 = 34
Octal
4 2
4 × 8 + 2 × 1 = 34
Hexadecimal
2 2
2 × 16 + 2 × 1 = 34
Read as powers of two: 32 + 2 = 34.
In historical numeral systems
Egyptian
3 hobbles, 4 strokes
3 × 10 + 4 × 1 = 34. The signs are simply repeated and added; where they sit on the line is a matter of layout, not value.
Babylonian
3 corner wedges + 4 vertical wedges
34 fits in a single sexagesimal place: 3 corner wedges + 4 vertical wedges.
Greek (Ionic)
lambda, then delta, marked as a numeral
lambda-delta + keraia
lambda + delta written in descending order and added — the letters carry their values wherever they stand, so this is addition, not place value.
Hebrew numerals
lamed, then dalet
lamed-dalet
lamed (30) + dalet (4) = 34, written in descending order.
Chinese numerals
sān shí sì
sān shí sì
三 before 十 multiplies it: 3 tens. 四 after it adds 4. The written form mirrors the arithmetic — "sān shí sì". The financial (anti-fraud) form is 參拾肆.
Maya
1 dot (upper, twenties place) over 2 bars + 4 dots (lower, units place)
1 × 20 + 14 = 34. Places stack vertically with the smallest at the bottom, so the upper group is worth twenty times the lower.
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
- Semiprime
Related numbers & connections
34 is a factor of 68 (34 × 2 = 68).
View 68 →Portugal and Spain share the Iberian Peninsula, and their codes sit in the same European block assigned in sequence rather than by geography.
View 351 →34 is the 9th number in the Fibonacci sequence.
Mathematically related
- is a factor of68
why?
Strength 0.50, confidence "high".
Nearby in a sequence
- is adjacent to351
why?
Strength 0.50, confidence "high".
Shares a distinctive class
- belongs toFibonacci sequence
why?
Strength 0.50, confidence "high".
Other connections
- is associated with724
why?
Strength 0.50, confidence "high".
Technology & computing
Xerography — the process behind every photocopier and laser printer — worked commercially because of element 34. A selenium-coated drum holds a static charge in the dark and loses it where light falls, so a projected image becomes a pattern of charge that toner sticks to. Selenium drums were standard from the first Xerox machines until organic photoconductors displaced them.
DocumentedTechnology & computingPeriod: 1950s onwards
Everyday life
Element 34 is in most medicated anti-dandruff shampoos: selenium sulfide slows the skin-cell turnover and fungal growth behind seborrhoeic dermatitis. It is one of the few places a trace element from the middle of the periodic table appears on a supermarket shelf by name.
DocumentedEveryday life
Mathematics
Every row, column and diagonal of a 4x4 magic square containing 1 to 16 sums to 34. Durer engraved one such square into his 1514 print Melencolia I, with the year itself worked into the bottom row.
DocumentedMathematicsPeriod: 151434 is the 9th Fibonacci number (1, 1, 2, 3, 5, 8, 13, 21, 34), each term the sum of the two preceding it.
DocumentedMathematics
Science
34 is the atomic number of selenium, an essential trace mineral.
DocumentedScience
Common questions
Why do all the rows of Dürer's magic square add to 34?
Same reason as the 3×3 square adding to 15: the numbers 1 to 16 total 136, and four rows share it equally, giving 34 each. Dürer's 1514 engraving Melencolia I contains one such square with the year worked into the bottom row — the middle two cells read 15 and 14.
What is selenium used for?
Two very different things. It is an essential dietary trace element, and selenium sulfide is the active ingredient in most medicated anti-dandruff shampoos. Industrially, selenium-coated drums made photocopying work: the coating holds a static charge in the dark and loses it where light falls, so a projected image becomes a pattern that toner sticks to.
Is 34 a prime number?
No, 34 is not prime.
What are the factors of 34?
The factors of 34 are 1, 2, 17, 34.
What is 34 in Roman numerals?
34 in Roman numerals is XXXIV. IV is subtractive: one before five — five minus one. Written additively it would be XXXIIII, 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: 5 reviewer-confirmed records, sourced and reviewed before publication.
Last reviewed: 15 July 2026