1,380,649
1,380,649 is the digit string of the Boltzmann constant, exactly 1.380649 × 10⁻²³ joules per kelvin since 2019.
- Odd
- Composite
Where 1,380,649 fits
Why 1,380,649 is special
It converts temperature into energy, and fixing it defined the kelvin. The old definition used the triple point of water, which made the unit depend on the isotopic composition of a particular sample — a definition that was reproducible only if everyone used water of the same origin.
1,380,649 is part of
Factors & digit properties
- Divisors (4)
- 1, 73, 18913, 1380649
- Prime factorisation
- 73 × 18913
- Digit sum
- 31
- Digital root
- 4
Representations
- Decimal
- 1380649
- Scientific notation
- 1.381 × 10^6
Roman numerals
Roman numerals as modelled here goes up to 3,999.
Binary
1 0 1 0 1 0 0 0 1 0 0 0 1 0 0 1 0 1 0 0 1
1 × 1,048,576 + 0 × 524,288 + 1 × 262,144 + 0 × 131,072 + 1 × 65,536 + 0 × 32,768 + 0 × 16,384 + 0 × 8,192 + 1 × 4,096 + 0 × 2,048 + 0 × 1,024 + 0 × 512 + 1 × 256 + 0 × 128 + 0 × 64 + 1 × 32 + 0 × 16 + 1 × 8 + 0 × 4 + 0 × 2 + 1 × 1 = 1,380,649
Octal
5 2 1 0 4 5 1
5 × 262,144 + 2 × 32,768 + 1 × 4,096 + 0 × 512 + 4 × 64 + 5 × 8 + 1 × 1 = 1,380,649
Hexadecimal
1 5 1 1 2 9
1 × 1,048,576 + 5 × 65,536 + 1 × 4,096 + 1 × 256 + 2 × 16 + 9 × 1 = 1,380,649
In historical numeral systems
Egyptian
1 Heh figure, 3 tadpoles, 8 fingers, 6 coils of rope, 4 hobbles, 9 strokes
1 × 1,000,000 + 3 × 100,000 + 8 × 10,000 + 6 × 100 + 4 × 10 + 9 × 1 = 1,380,649. 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
- Semiprime
Related numbers & connections
1380649 appears in Numbers in physics, the topic covering numbers that carry a documented physics fact.
Numbers Around Us
- appears inPhysics
why?
Strength 0.50, confidence "high".
Science
The digit string of the Boltzmann constant in joules per kelvin is 1,380,649 (worldwide, since the 2019 redefinition). Fixing it is what defines the kelvin. Temperature is no longer anchored to a property of water but to the energy a degree corresponds to, so the triple point of water is now a measured quantity rather than a definition.
DocumentedScienceGeography: worldwide, since the 2019 redefinition
Common questions
Is 1,380,649 a prime number?
No, 1,380,649 is not prime.
What are the factors of 1,380,649?
The factors of 1,380,649 are 1, 73, 18913, 1380649.
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