99,942
99942 Apophis is the asteroid that briefly carried the highest impact risk ever recorded.
- Even
- Composite
Where 99,942 fits
Why 99,942 is special
In 2004 it reached level 4 on the Torino scale — the highest any object has been assigned — before further observations ruled out an impact. It will pass closer than geostationary satellites in 2029.
99,942 is part of
Factors & digit properties
- Divisors (8)
- 1, 2, 3, 6, 16657, 33314, 49971, 99942
- Prime factorisation
- 2 × 3 × 16657
- Digit sum
- 33
- Digital root
- 6
Representations
- Decimal
- 99942
- Scientific notation
- 9.994 × 10^4
Roman numerals
Roman numerals as modelled here goes up to 3,999.
Binary
1 1 0 0 0 0 1 1 0 0 1 1 0 0 1 1 0
1 × 65,536 + 1 × 32,768 + 0 × 16,384 + 0 × 8,192 + 0 × 4,096 + 0 × 2,048 + 1 × 1,024 + 1 × 512 + 0 × 256 + 0 × 128 + 1 × 64 + 1 × 32 + 0 × 16 + 0 × 8 + 1 × 4 + 1 × 2 + 0 × 1 = 99,942
Octal
3 0 3 1 4 6
3 × 32,768 + 0 × 4,096 + 3 × 512 + 1 × 64 + 4 × 8 + 6 × 1 = 99,942
Hexadecimal
1 8 6 6 6
1 × 65,536 + 8 × 4,096 + 6 × 256 + 6 × 16 + 6 × 1 = 99,942
Read as powers of two: 65,536 + 32,768 + 1,024 + 512 + 64 + 32 + 4 + 2 = 99,942.
In historical numeral systems
Egyptian
9 fingers, 9 lotuses, 9 coils of rope, 4 hobbles, 2 strokes
9 × 10,000 + 9 × 1,000 + 9 × 100 + 4 × 10 + 2 × 1 = 99,942. The signs are simply repeated and added; where they sit on the line is a matter of layout, not value.
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
- Abundant number
- Happy number
Related numbers & connections
Both are small near-Earth asteroids in the size range producing regional rather than global effects.
View 2340 →Science
Apophis briefly rated 4 on the Torino impact-hazard scale in 2004, higher than any object before or since. Refined orbits eliminated the risk, and it will still pass inside geostationary orbit in 2029.
DocumentedSciencePeriod: 2004
Common questions
Is 99,942 a prime number?
No, 99,942 is not prime.
What are the factors of 99,942?
The factors of 99,942 are 1, 2, 3, 6, 16657, 33314, 49971, 99942.
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