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Prime Factor


A prime factor is a factor that is prime, i.e., one that cannot itself be factored. In general, a prime factorization takes the form

 n=p_1^(alpha_1)p_2^(alpha_2)...p_k^(alpha_k),

where p_i are prime factors and alpha_i are their orders. prime factorization can be performed in the Wolfram Language using the command FactorInteger[n], which returns a list of (p_i,alpha_i) pairs.

The following table gives the prime factorization for the positive integers <=50.

nprime fac.nprime fac.nprime fac.nprime fac.nprime fac.
111111213·731314141
22122^2·3222·11322^5422·3·7
3313132323333·114343
42^2142·7242^3·3342·17442^2·11
55153·5255^2355·7453^2·5
62·3162^4262·13362^2·3^2462·23
771717273^337374747
82^3182·3^2282^2·7382·19482^4·3
93^219192929393·13497^2
102·5202^2·5302·3·5402^3·5502·5^2

Two standard arithmetic functions count prime factors. The prime nu function omega(n) counts distinct prime factors, while the prime omega function Omega(n) counts them with multiplicity. For example, 4=2·2 gives omega(4)=1 and Omega(4)=2 (Hardy and Wright 1979, p. 354). The notation nu(n) is also used for omega(n), while r(n) can denote either count, so care is needed unless the convention is stated. The h(N) appearing in Veritasium (2025) is instead a local notation for the number of Goldbach partitions of N.


See also

Dickman Function, Distinct Prime Factors, Divisor Function, Factor, Greatest Prime Factor, Least Prime Factor, Liouville Function, Mertens Constant, Pólya Conjecture, Prime Factorization, Prime Factorization Algorithms, Prime Number, Prime Nu Function, Prime Omega Function, Primitive Prime Factor, Round Number, Sum of Prime Factors Explore this topic in the MathWorld classroom

Related Wolfram sites

https://functions.wolfram.com/NumberTheoryFunctions/FactorInteger/

Explore with Wolfram|Alpha

References

Hardy, G. H. and Wright, E. M. §22.10 in An Introduction to the Theory of Numbers, 5th ed. Oxford, England: Clarendon Press, p. 354, 1979.Veritasium. "The Obviously True Theorem No One Can Prove." Jun. 20, 2025. https://www.youtube.com/watch?v=x32Zq-XvID4.

Referenced on Wolfram|Alpha

Prime Factor

Cite this as:

Weisstein, Eric W. "Prime Factor." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/PrimeFactor.html

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