38
The 38th parallel divided Korea in 1945 — a line chosen from a wall map in a hurry and never meant as a border. 38 is also the atomic number of strontium, the element that makes fireworks burn red.
- Even
- Composite
Where 38 fits
Why 38 is special
38 is a quieter number mathematically (2 × 19) — its interest lies in its neighbours rather than a property of its own.
Same number, different meanings
How 38 is understood across different contexts — never implying one meaning because of another.
- Mathematics
38 is a quieter number mathematically (2 × 19) — its interest lies in its neighbours rather than a property of its own.
- Science
The rate at which the Moon is receding from the Earth is 38 millimetres per year (the Earth-Moon system). Measured by bouncing lasers off reflectors left by the Apollo missions, which is why the figure is known to the millimetre.
- Technology & computing
Element 38 is the reason a firework or a marine distress flare burns red. Strontium salts emit strongly in the deep red when heated, and no cheaper element produces the same colour cleanly, so strontium nitrate and strontium carbonate remain standard in pyrotechnic formulations. The same emission makes strontium easy to identify by flame test, which is how it was first distinguished as a separate element in the 1790s.
- Geography
The 38th parallel north was chosen in August 1945 by two US officers dividing Korea into Soviet and American occupation zones, reportedly working from a National Geographic map because it put Seoul on the southern side. The line was never intended as a border. The armistice line that ended the fighting in 1953 crosses it diagonally, so the modern Demilitarised Zone follows the parallel only loosely.
38 is part of
Factors & digit properties
- Divisors (4)
- 1, 2, 19, 38
- Prime factorisation
- 2 × 19
- Digit sum
- 11
- Digital root
- 2
Representations
- Decimal
- 38
- Scientific notation
- 3.800 × 10^1
Roman numerals
X X X V I I I
Binary
1 0 0 1 1 0
1 × 32 + 0 × 16 + 0 × 8 + 1 × 4 + 1 × 2 + 0 × 1 = 38
Octal
4 6
4 × 8 + 6 × 1 = 38
Hexadecimal
2 6
2 × 16 + 6 × 1 = 38
Read as powers of two: 32 + 4 + 2 = 38.
In historical numeral systems
Egyptian
3 hobbles, 8 strokes
3 × 10 + 8 × 1 = 38. The signs are simply repeated and added; where they sit on the line is a matter of layout, not value.
Babylonian
3 corner wedges + 8 vertical wedges
38 fits in a single sexagesimal place: 3 corner wedges + 8 vertical wedges.
Greek (Ionic)
lambda, then eta, marked as a numeral
lambda-eta + keraia
lambda + eta 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 het
lamed-het
lamed (30) + het (8) = 38, written in descending order.
Chinese numerals
sān shí bā
sān shí bā
三 before 十 multiplies it: 3 tens. 八 after it adds 8. The written form mirrors the arithmetic — "sān shí bā". The financial (anti-fraud) form is 參拾捌.
Maya
1 dot (upper, twenties place) over 3 bars + 3 dots (lower, units place)
1 × 20 + 18 = 38. 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
19 is a factor of 38 (19 × 2 = 38).
View 19 →38 appears in Numbers in space, the topic covering numbers that carry a documented astronomy fact.
Science
The rate at which the Moon is receding from the Earth is 38 millimetres per year (the Earth-Moon system). Measured by bouncing lasers off reflectors left by the Apollo missions, which is why the figure is known to the millimetre.
DocumentedScienceGeography: the Earth-Moon systemThere are roughly 38 trillion bacteria living in and on an adult human body (adults). A 2016 recount with a stated spread of about 25 per cent, which overturned the widely repeated claim that bacteria outnumber human cells ten to one. The ratio is closer to one to one.
DocumentedScienceGeography: adults38 is the atomic number of strontium. Its salts burn a vivid crimson, which is what produces the red in fireworks and emergency flares.
DocumentedScience
Technology & computing
Element 38 is the reason a firework or a marine distress flare burns red. Strontium salts emit strongly in the deep red when heated, and no cheaper element produces the same colour cleanly, so strontium nitrate and strontium carbonate remain standard in pyrotechnic formulations. The same emission makes strontium easy to identify by flame test, which is how it was first distinguished as a separate element in the 1790s.
DocumentedTechnology & computing
Geography
The 38th parallel north was chosen in August 1945 by two US officers dividing Korea into Soviet and American occupation zones, reportedly working from a National Geographic map because it put Seoul on the southern side. The line was never intended as a border. The armistice line that ended the fighting in 1953 crosses it diagonally, so the modern Demilitarised Zone follows the parallel only loosely.
DocumentedGeographyGeography: Korean PeninsulaPeriod: 1945 onwards
Mathematics
38 sits directly between the perfect square 36 (6²) and the prime 37, and factors as 2 × 19.
DocumentedMathematics
Common questions
Why is Korea divided at the 38th parallel?
It was picked in a hurry. In August 1945, two American officers were asked to propose an occupation line and chose the 38th parallel from a wall map, largely because it put Seoul on the American side. It was never meant to be a border. The armistice line that ended the fighting in 1953 crosses it diagonally, so the modern Demilitarised Zone follows the parallel only loosely.
Is 38 a prime number?
No, 38 is not prime.
What are the factors of 38?
The factors of 38 are 1, 2, 19, 38.
What is 38 in Roman numerals?
38 in Roman numerals is XXXVIII.
About this page's data
Mathematical facts:computed directly from the number's value — nothing to source or verify externally.
Contextual records: 6 reviewer-confirmed records, sourced and reviewed before publication.
Last reviewed: 15 July 2026