|Numeral systems by culture|
|Positional systems by base|
|Non-standard positional numeral systems|
|List of numeral systems|
Senary may be considered useful in the study of prime numbers since all primes other than 2 and 3, when expressed in base-six, have 1 or 5 as the final digit. Writing out the prime numbers in base-six (and using the subscript 6 to denote that these are senary numbers), the first few primes are
That is, for every prime number p with , one has the modular arithmetic relations that either or : the final digits is a 1 or a 5. This is proved by contradiction. For integer n:
- If n mod 6 = 0, 6|n
- If n mod 6 = 2, 2|n
- If n mod 6 = 3, 3|n
- If n mod 6 = 4, 2|n
Furthermore, all known perfect numbers besides 6 itself have 44 as the final two digits when expressed in base 6.
Finger counting 
Each regular human hand may be said to have six unambiguous positions; a fist, one finger (or thumb) extended, two, three, four and then all five extended.
If the right hand is used to represent a unit, and the left to represent the 'sixes', it becomes possible for one person to represent the values from zero to 55senary (35decimal) with their fingers, rather than the usual ten obtained in standard finger counting. e.g. if three fingers are extended on the left hand and four on the right, 34senary is represented. This is equivalent to 3 × 6 + 4 which is 22decimal.
Which hand is used for the 'sixes' and which the units is down to preference on the part of the counter, however when viewed from the counter's perspective, using the left hand as the most significant digit correlates with the written representation of the same senary number.
Other finger counting systems, such as chisanbop or finger binary, allow counting to 99, 1,023, or even higher depending on the method (though not necessarily senary in nature). The English monk and historian Bede in the first chapter of De temporum ratione, (725), entitled "Tractatus de computo, vel loquela per gestum digitorum", which allowed counting up to 9,999 on two hands.
Prime factors of the base: 2, 5
Prime factors of the base: 2, 3
of the denominator
|Positional representation||Positional representation||Prime factors
of the denominator
|1/3||3||0.3333... = 0.3||0.2||3||1/3|
|1/5||5||0.2||0.1111... = 0.1||5||1/5|
|1/6||2, 3||0.16||0.1||2, 3||1/10|
|1/10||2, 5||0.1||0.03||2, 5||1/14|
|1/12||2, 3||0.083||0.03||2, 3||1/20|
|1/14||2, 7||0.0714285||0.023||2, 11||1/22|
|1/15||3, 5||0.06||0.02||3, 5||1/23|
|1/18||2, 3||0.05||0.02||2, 3||1/30|
Natural languages 
The Ndom language of Papua New Guinea is reported to have senary numerals. Mer means 6, mer an thef means 6×2 = 12, nif means 36, and nif thef means 36×2 = 72. Proto-Uralic is also suspected to have used senary numerals.
See also 
- Diceware has a way of encoding base 6 values into pronounceable words, using a standardized list of 7,776 distinct words
- "Dactylonomy". Laputan Logic. 16 November 2006. Retrieved May 12, 2012.
- Bloom, Jonathan M. (2001). "Hand sums: The ancient art of counting with your fingers". Yale University Press. Retrieved May 12, 2012.
- Owens, Kay (2001), "The Work of Glendon Lean on the Counting Systems of Papua New Guinea and Oceania", Mathematics Education Research Journal 13 (1): 47–71, doi:10.1007/BF03217098