71
71 is a prime number, the atomic number of lutetium, and close to the commonly cited ~71% figure for the proportion of Earth's surface covered by water.
- Odd
- Prime
Where 71 fits
Why 71 is special
71's near-coincidental match with Earth's water coverage is a genuine, widely cited approximate figure in Earth science, not a mathematical property of the number itself.
Same number, different meanings
How 71 is understood across different contexts — never implying one meaning because of another.
- Mathematics
71's near-coincidental match with Earth's water coverage is a genuine, widely cited approximate figure in Earth science, not a mathematical property of the number itself.
- Science
71 is the atomic number of lutetium.
- Geography
Approximately 71% of Earth's surface is covered by water, mostly oceans — one of the most widely cited approximate figures in Earth science.
71 is part of
Factors & digit properties
- Divisors (2)
- 1, 71
- Prime factorisation
- 71
- Digit sum
- 8
- Digital root
- 8
Representations
- Decimal
- 71
- Binary
- 1000111
- Octal
- 107
- Hexadecimal
- 47
- Roman numeral
- LXXI
- Scientific notation
- 7.100 × 10^1
Other mathematical patterns
- Deficient number
- Twin prime
Related numbers & connections
71 and 73 are twin primes — two primes exactly two apart.
View 73 →Shares a distinctive class
- is associated with73
why?
Strength 0.50, confidence "high".
Science
71 is the atomic number of lutetium.
DocumentedScience
Geography
Approximately 71% of Earth's surface is covered by water, mostly oceans — one of the most widely cited approximate figures in Earth science.
Widely documentedGeography
Common questions
Is 71 a prime number?
Yes, 71 is prime — it has exactly two positive divisors: 1 and itself.
What are the factors of 71?
The factors of 71 are 1, 71.
What is 71 in Roman numerals?
71 in Roman numerals is LXXI.
About this page's data
Mathematical facts:computed directly from the number's value — nothing to source or verify externally.
Contextual records: 2 reviewer-confirmed records, sourced and reviewed before publication.
Last reviewed: 15 July 2026