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Euler's Totient Function φ(n) Calculator

Count of integers ≤ n coprime to n.

Calculates Euler's totient φ(n) = n × Π(1 − 1/p) for each distinct prime p dividing n. Used in RSA encryption and modular arithmetic.

Priya Venkatesan By Priya Venkatesan
Published Last reviewed 1 min read

Inputs

Results

Enter values and click Calculate to see results.
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How to use this calculator

  1. Fill in the inputs above using the units you already have.
  2. Values update automatically as you type — no submit button needed.
  3. Hover any result row for the underlying formula and intermediate values.

Formula

φ(n) = n × Π (1 − 1/p)

In depth

Calculates Euler's totient φ(n) = n × Π(1 − 1/p) for each distinct prime p dividing n. Used in RSA encryption and modular arithmetic.