145
145 equals the sum of the factorials of its own digits.
- Odd
- Composite
Where 145 fits
Why 145 is special
1! + 4! + 5! = 1 + 24 + 120 = 145. Only four numbers in base ten do this: 1, 2, 145 and 40,585. The list is complete and proven, not merely unfinished — beyond seven digits the factorials cannot keep up with the number itself.
Factors & digit properties
- Divisors (4)
- 1, 5, 29, 145
- Prime factorisation
- 5 × 29
- Digit sum
- 10
- Digital root
- 1
Representations
- Decimal
- 145
- Binary
- 10010001
- Octal
- 221
- Hexadecimal
- 91
- Roman numeral
- CXLV
- Scientific notation
- 1.450 × 10^2
Other mathematical patterns
- Deficient number
- Pentagonal number
- Semiprime
Related numbers & connections
Both equal the sum of the factorials of their own digits. With 1 and 2 they are the complete set in base ten, and the completeness is proven rather than merely unextended.
View 40585 →The engine and the regional jet it powers defined the fifty-seat category together.
View 3007 →Technology & computing
The Embraer ERJ 145 established the 50-seat regional jet market from 1996, replacing turboprops on thin routes before fuel prices made that size uneconomic.
DocumentedTechnology & computingGeography: Brazil, operated worldwidePeriod: 1996–
Mathematics
1! + 4! + 5! = 145. Only 1, 2, 145 and 40,585 equal the sum of their own digits' factorials in base ten, and the list is proven complete rather than merely unextended — past seven digits the factorials cannot keep pace with the number.
DocumentedMathematics
Common questions
Is 145 a prime number?
No, 145 is not prime.
What are the factors of 145?
The factors of 145 are 1, 5, 29, 145.
What is 145 in Roman numerals?
145 in Roman numerals is CXLV.
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: 3 August 2026