801
The Class 801 runs on electricity but carries a diesel engine anyway.
- Odd
- Composite
Where 801 fits
Why 801 is special
The engine exists only to move the train off the electrified network in a failure, which is an unusual amount of dead weight to carry for a rare event.
Factors & digit properties
- Divisors (6)
- 1, 3, 9, 89, 267, 801
- Prime factorisation
- 3^2 × 89
- Digit sum
- 9
- Digital root
- 9
Representations
- Decimal
- 801
- Scientific notation
- 8.010 × 10^2
Roman numerals
D C C C I
Binary
1 1 0 0 1 0 0 0 0 1
1 × 512 + 1 × 256 + 0 × 128 + 0 × 64 + 1 × 32 + 0 × 16 + 0 × 8 + 0 × 4 + 0 × 2 + 1 × 1 = 801
Octal
1 4 4 1
1 × 512 + 4 × 64 + 4 × 8 + 1 × 1 = 801
Hexadecimal
3 2 1
3 × 256 + 2 × 16 + 1 × 1 = 801
Read as powers of two: 512 + 256 + 32 + 1 = 801.
In historical numeral systems
Egyptian
8 coils of rope, 1 stroke
8 × 100 + 1 × 1 = 801. The signs are simply repeated and added; where they sit on the line is a matter of layout, not value.
Babylonian
1 corner wedge + 3 vertical wedges (sixties place), 2 corner wedges + 1 vertical wedge (units place)
13 × 60 + 21 = 801. Places are separated by a space on the tablet, with the higher place written first.
Greek (Ionic)
omega, then alpha, marked as a numeral
omega-alpha + keraia
omega + alpha written in descending order and added — the letters carry their values wherever they stand, so this is addition, not place value.
Hebrew numerals
tav, then tav, then alef
tav-tav-alef
tav (400) + tav (400) + alef (1) = 801, written in descending order.
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
- Harshad (Niven) number
- Lucky number (mathematical sieve)
Related numbers & connections
The 801 is the electric-only member of the family, carrying a diesel generator solely for the day the wires fail.
View 800 →Other connections
- is associated with800
why?
Strength 0.50, confidence "high".
Technology & computing
The British Rail Class 801 is an electric multiple unit fitted with a diesel generator intended for emergency movement rather than routine operation on unelectrified track.
DocumentedTechnology & computingGeography: United KingdomPeriod: 2018–
Common questions
Is 801 a prime number?
No, 801 is not prime.
What are the factors of 801?
The factors of 801 are 1, 3, 9, 89, 267, 801.
What is 801 in Roman numerals?
801 in Roman numerals is DCCCI.
About this page's data
Mathematical facts:computed directly from the number's value — nothing to source or verify externally.
Contextual records: 1 reviewer-confirmed record, sourced and reviewed before publication.
Last reviewed: 15 July 2026