Número de Divisores τ(n)
- Created by
- Renato Passos, Eng. de Software
- Reviewed by
- Renato Passos, Eng. de Software
Last updated: Apr 18, 2026
Formula
τ(n) = #divisores
About this calculator
This calculator determines the number of positive divisors of a positive integer n, denoted by τ(n) (tau of n). The function τ(n) counts exactly how many positive integers divide n without leaving a remainder. For example, τ(12) = 6, because the divisors of 12 are 1, 2, 3, 4, 6, and 12. The calculation is based on the prime factorization of n: if n = p₁^a₁ × p₂^a₂ × ... × p_k^a_k, then τ(n) = (a₁+1)(a₂+1)...(a_k+1).
To use the calculator, simply enter a positive integer in the input field and click 'Calculate'. The result will display the value of τ(n) and, in many cases, also the list of divisors. This tool is useful for mathematics students, teachers, and enthusiasts who need to explore number properties, such as classifying numbers as primes (τ=2), perfect squares (odd τ), or highly composite numbers.
Use cases include checking if a number is prime (τ=2), discovering if a number is a perfect square (odd τ), or comparing the number of divisors between two numbers. Caveats: the calculator only accepts positive integers; negative or decimal values will produce an error. Additionally, very large numbers may require extra processing, but the tool handles reasonable values.
Frequently asked questions
What does τ(n) = 2 mean?
It means that n has exactly two positive divisors: 1 and itself. Therefore, n is a prime number.
Why is the τ of a perfect square odd?
Because in the prime factorization, all exponents are even. Thus, each (a_i+1) is odd, and the product of odd numbers is odd.
Does the calculator accept numbers with more than 10 digits?
Yes, as long as the number is a positive integer. However, very large numbers may take a bit longer to process.
What happens if I enter 0 or a negative number?
The calculator will display an error message, since τ(n) is defined only for positive integers.
How does the calculator find the divisors?
It performs the prime factorization of the number and then generates all possible products of the prime powers, listing all divisors.