18,416
18,416 is the partner of 17,296 in Fermat's amicable pair.
- Even
- Composite
Why 18,416 is special
Their divisors sum to each other. Al-Farisi had described the same pair in the thirteenth century, which European mathematicians did not know.
Factors & digit properties
- Divisors (10)
- 1, 2, 4, 8, 16, 1151, 2302, 4604, 9208, 18416
- Prime factorisation
- 2^4 × 1151
- Digit sum
- 20
- Digital root
- 2
Representations
- Decimal
- 18416
- Scientific notation
- 1.842 × 10^4
Roman numerals
Roman numerals as modelled here goes up to 3,999.
Binary
1 0 0 0 1 1 1 1 1 1 1 0 0 0 0
1 × 16,384 + 0 × 8,192 + 0 × 4,096 + 0 × 2,048 + 1 × 1,024 + 1 × 512 + 1 × 256 + 1 × 128 + 1 × 64 + 1 × 32 + 1 × 16 + 0 × 8 + 0 × 4 + 0 × 2 + 0 × 1 = 18,416
Octal
4 3 7 6 0
4 × 4,096 + 3 × 512 + 7 × 64 + 6 × 8 + 0 × 1 = 18,416
Hexadecimal
4 7 f 0
4 × 4,096 + 7 × 256 + f × 16 + 0 × 1 = 18,416
Read as powers of two: 16,384 + 1,024 + 512 + 256 + 128 + 64 + 32 + 16 = 18,416.
In historical numeral systems
Egyptian
1 finger, 8 lotuses, 4 coils of rope, 1 hobble, 6 strokes
1 × 10,000 + 8 × 1,000 + 4 × 100 + 1 × 10 + 6 × 1 = 18,416. 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
- Deficient number
Mathematics
The pair Fermat published had been described by al-Farisi in the thirteenth century. Rediscovery without knowledge of earlier work is a recurring pattern where scholarly traditions were not in contact.
DocumentedMathematics
Common questions
Is 18,416 a prime number?
No, 18,416 is not prime.
What are the factors of 18,416?
The factors of 18,416 are 1, 2, 4, 8, 16, 1151, 2302, 4604, 9208, 18416.
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