40
40 recurs as a symbolic period of trial or transition across several religious traditions and gave English the word "quarantine".
- Even
- Composite
Where 40 fits
Why 40 is special
40 is one of the richest cross-cultural numbers precisely because its significance is entirely traditional and textual, not mathematical: 40 days and nights of rain in the Genesis flood narrative, 40 years of wandering in the Exodus narrative, Jesus's 40 days in the wilderness in the Christian Gospels, and the Venetian "quaranta giorni" (forty days) of ship isolation that gave English "quarantine".
Same number, different meanings
How 40 is understood across different contexts — never implying one meaning because of another.
- Mathematics
40 is one of the richest cross-cultural numbers precisely because its significance is entirely traditional and textual, not mathematical: 40 days and nights of rain in the Genesis flood narrative, 40 years of wandering in the Exodus narrative, Jesus's 40 days in the wilderness in the Christian Gospels, and the Venetian "quaranta giorni" (forty days) of ship isolation that gave English "quarantine".
- History
The English word "quarantine" derives from the Venetian "quaranta giorni" (forty days) — the isolation period imposed on ships arriving from plague-affected ports in 14th–15th century Venice.
- Religion & belief
40 days and nights of rain is the duration given for the flood in the Genesis narrative (Hebrew Bible/Old Testament); 40 years of wilderness wandering appears in the Exodus narrative, and 40 days of fasting/temptation in the wilderness appears in the Christian Gospels' account of Jesus.
Factors & digit properties
- Divisors (8)
- 1, 2, 4, 5, 8, 10, 20, 40
- Prime factorisation
- 2^3 × 5
- Digit sum
- 4
- Digital root
- 4
Representations
- Decimal
- 40
- Binary
- 101000
- Octal
- 50
- Hexadecimal
- 28
- Roman numeral
- XL
- Scientific notation
- 4.000 × 10^1
Other mathematical patterns
- Abundant number
- Harshad (Niven) number
Related numbers & connections
20 is a factor of 40 (20 × 2 = 40).
View 20 →Mathematically related
- has factor20
why?
Strength 0.50, confidence "high".
History
The English word "quarantine" derives from the Venetian "quaranta giorni" (forty days) — the isolation period imposed on ships arriving from plague-affected ports in 14th–15th century Venice.
DocumentedHistoryGeography: VenicePeriod: 14th–15th centuryThe English word "quarantine" derives from the Venetian "quaranta giorni" (forty days) — the isolation period imposed on ships arriving from plague-affected ports in 14th–15th century Venice.
DocumentedHistoryGeography: VenicePeriod: 14th–15th century
Religion & belief
40 days and nights of rain is the duration given for the flood in the Genesis narrative (Hebrew Bible/Old Testament); 40 years of wilderness wandering appears in the Exodus narrative, and 40 days of fasting/temptation in the wilderness appears in the Christian Gospels' account of Jesus.
DocumentedReligion & beliefCulture: Jewish and Christian tradition
Common questions
Is 40 a prime number?
No, 40 is not prime.
What are the factors of 40?
The factors of 40 are 1, 2, 4, 5, 8, 10, 20, 40.
What is 40 in Roman numerals?
40 in Roman numerals is XL.
About this page's data
Mathematical facts:computed directly from the number's value — nothing to source or verify externally.
Contextual records: 3 reviewer-confirmed records, sourced and reviewed before publication.
Last reviewed: 15 July 2026