2600
2,600 Hz was the tone that unlocked the US long-distance telephone network.
- Even
- Composite
Where 2600 fits
Why 2600 is special
AT&T used a 2,600 Hz signal internally to mark a line as idle, so a caller who produced that tone could take control of the trunk. A toy whistle from a cereal packet happened to emit it, which is how the discovery spread.
Factors & digit properties
- Divisors (24)
- 1, 2, 4, 5, 8, 10, 13, 20, 25, 26, 40, 50, 52, 65, 100, 104, 130, 200, 260, 325, 520, 650, 1300, 2600
- Prime factorisation
- 2^3 × 5^2 × 13
- Digit sum
- 8
- Digital root
- 8
Representations
- Decimal
- 2600
- Binary
- 101000101000
- Octal
- 5050
- Hexadecimal
- a28
- Roman numeral
- MMDC
- Scientific notation
- 2.600 × 10^3
Other mathematical patterns
- Abundant number
- Harshad (Niven) number
Related numbers & connections
The 7800 retained 2600 cartridge compatibility and was shelved for two years during Atari's sale.
View 7800 →Technology & computing
The network carried its control signals on the same channel as the voice, so anyone who could reproduce a 2,600 Hz tone could instruct it. The fix was to move signalling onto a separate channel, which is why the same trick cannot work today.
DocumentedTechnology & computingCulture: American telephone phreakingPeriod: 1960s–1970sThe Atari 2600 had too little memory to hold a screen image, so programs had to construct each scanline as the television beam drew it. The technique became known as racing the beam.
DocumentedTechnology & computingGeography: United StatesPeriod: 1977–1992
Common questions
Is 2600 a prime number?
No, 2600 is not prime.
What are the factors of 2600?
The factors of 2600 are 1, 2, 4, 5, 8, 10, 13, 20, 25, 26, 40, 50, 52, 65, 100, 104, 130, 200, 260, 325, 520, 650, 1300, 2600.
What is 2600 in Roman numerals?
2600 in Roman numerals is MMDC.
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