Numberwise

406

406 MHz is the frequency of emergency distress beacons detected by satellite.

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Where 406 fits

Where 406 fits: Mathematics, Related numbersMathematics: Triangular number. Related numbers: 7700, 121.MathematicsTriangular numberRelated numbers7700121406
406 connects to 2 worlds: mathematics, related numbers.

Why 406 is special

A beacon on this frequency is picked up by an international satellite network and located to within a few kilometres, or metres if it transmits GPS. The system is free at the point of use and has been credited with tens of thousands of rescues.

406 is part of

Triangular numbers

Factors & digit properties

Divisors (8)
1, 2, 7, 14, 29, 58, 203, 406
Prime factorisation
2 × 7 × 29
Digit sum
10
Digital root
1

Representations

Decimal
406
Binary
110010110
Octal
626
Hexadecimal
196
Roman numeral
CDVI
Scientific notation
4.060 × 10^2

Other mathematical patterns

  • Triangular number
  • Deficient number

Related numbers & connections

Connection
Two ways of declaring an emergency: a satellite-tracked distress beacon, and a transponder code that tells every radar screen in range. One works anywhere on Earth, the other only where radar reaches.

Two ways of declaring an emergency: a satellite-tracked distress beacon, and a transponder code that tells every radar screen in range. One works anywhere on Earth, the other only where radar reaches.

View 7700 →

Other connections

  • contrasts with7700
    why?

    Strength 0.50, confidence "high".

  • contrasts with121
    why?

    Strength 0.50, confidence "high".

How is 406 connected to another number? →

Technology & computing

  • 406 MHz beacons are tracked by an international satellite system operated jointly by several states, which locates a signal within kilometres anywhere on Earth. The older 121.5 MHz system was switched off in 2009 because it produced too many false alerts to be useful.

    DocumentedTechnology & computingGeography: International — Cospas-Sarsat participating states

  • 406 MHz distress beacons are processed by the Cospas-Sarsat system and carry a registered identifier, unlike the analogue 121.5 MHz beacons whose satellite monitoring ended in 2009.

    DocumentedTechnology & computingGeography: International — Cospas-Sarsat participating statesPeriod: 1982–

Common questions

Is 406 a prime number?

No, 406 is not prime.

What are the factors of 406?

The factors of 406 are 1, 2, 7, 14, 29, 58, 203, 406.

What is 406 in Roman numerals?

406 in Roman numerals is CDVI.

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