75
75 per cent is three quarters, one of the few percentages that needs no explanation. A 75th anniversary is a diamond jubilee in some traditions, though British royal usage puts diamond at 60. 75 is the atomic number of rhenium.
- Odd
- Composite
Where 75 fits
Why 75 is special
75 sits one tier above the 25th 'silver' and 50th 'golden' anniversary milestones in the same naming tradition.
75 connects to:
- 25 — has factor
Same number, different meanings
How 75 is understood across different contexts — never implying one meaning because of another.
- Mathematics
75 sits one tier above the 25th 'silver' and 50th 'golden' anniversary milestones in the same naming tradition.
- Everyday life
The internal temperature poultry must reach to be safe is 75 degrees Celsius (United Kingdom and EU guidance). Time matters as well as temperature: the same lethality is reached at 70 degrees held for two minutes. The single number is the version that fits on a label.
- Culture
A 75th anniversary is traditionally termed a 'diamond jubilee' in the Western anniversary-naming convention, one tier above the 25th 'silver' and 50th 'golden' milestones.
- Science
75 is the atomic number of rhenium, which has one of the highest melting points of any element. Rhenium-bearing superalloys let jet-engine turbine blades run hotter, and hotter engines are more efficient.
Factors & digit properties
- Divisors (6)
- 1, 3, 5, 15, 25, 75
- Prime factorisation
- 3 × 5^2
- Digit sum
- 12
- Digital root
- 3
Representations
- Decimal
- 75
- Scientific notation
- 7.500 × 10^1
Roman numerals
L X X V
Binary
1 0 0 1 0 1 1
1 × 64 + 0 × 32 + 0 × 16 + 1 × 8 + 0 × 4 + 1 × 2 + 1 × 1 = 75
Octal
1 1 3
1 × 64 + 1 × 8 + 3 × 1 = 75
Hexadecimal
4 b
4 × 16 + b × 1 = 75
Read as powers of two: 64 + 8 + 2 + 1 = 75.
In historical numeral systems
Egyptian
7 hobbles, 5 strokes
7 × 10 + 5 × 1 = 75. The signs are simply repeated and added; where they sit on the line is a matter of layout, not value.
Babylonian
1 vertical wedge (sixties place), 1 corner wedge + 5 vertical wedges (units place)
1 × 60 + 15 = 75. Places are separated by a space on the tablet, with the higher place written first.
Greek (Ionic)
omicron, then epsilon, marked as a numeral
omicron-epsilon + keraia
omicron + epsilon written in descending order and added — the letters carry their values wherever they stand, so this is addition, not place value.
Hebrew numerals
ayin, then he
ayin-he
ayin (70) + he (5) = 75, written in descending order.
Chinese numerals
qī shí wǔ
qī shí wǔ
七 before 十 multiplies it: 7 tens. 五 after it adds 5. The written form mirrors the arithmetic — "qī shí wǔ". The financial (anti-fraud) form is 柒拾伍.
Maya
3 dots (upper, twenties place) over 3 bars (lower, units place)
3 × 20 + 15 = 75. 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
- Lucky number (mathematical sieve)
Related numbers & connections
25 is a factor of 75 (25 × 3 = 75).
View 25 →Mathematically related
- has factor25
why?
Strength 0.50, confidence "high".
Everyday life
The internal temperature poultry must reach to be safe is 75 degrees Celsius (United Kingdom and EU guidance). Time matters as well as temperature: the same lethality is reached at 70 degrees held for two minutes. The single number is the version that fits on a label.
DocumentedEveryday lifeGeography: United Kingdom and EU guidance75 per cent is three quarters, the fraction people reach for after a half when describing most of something. It sits alongside 25 and 50 as one of the three percentage landmarks that need no explanation in ordinary speech.
DocumentedEveryday life
Culture
A 75th anniversary is traditionally termed a 'diamond jubilee' in the Western anniversary-naming convention, one tier above the 25th 'silver' and 50th 'golden' milestones.
Widely documentedCultureGeography: Western/English-speaking traditions
Science
75 is the atomic number of rhenium, which has one of the highest melting points of any element. Rhenium-bearing superalloys let jet-engine turbine blades run hotter, and hotter engines are more efficient.
DocumentedScience
Common questions
Is a diamond jubilee 60 years or 75?
Both, depending on where you are and what is being marked. British usage settled on 60 for royal jubilees — Queen Victoria's Diamond Jubilee in 1897 marked 60 years — while 75 is the more common diamond anniversary in some wedding-anniversary lists. The naming conventions are commercial and national conventions rather than a single agreed scheme.
Is 75 a prime number?
No, 75 is not prime.
What are the factors of 75?
The factors of 75 are 1, 3, 5, 15, 25, 75.
What is 75 in Roman numerals?
75 in Roman numerals is LXXV.
About this page's data
Mathematical facts:computed directly from the number's value — nothing to source or verify externally.
Contextual records: 4 reviewer-confirmed records, sourced and reviewed before publication.
Last reviewed: 15 July 2026