Preprint proposing an analytical approximation to Euler’s totient function φ(n) when n = pq with large primes.
While not exact, the method (the “Kaoru Method”) shows decreasing relative error as n grows and p, q are more balanced.
Given the central role of φ(n) in RSA, the question is whether such approximations could have cryptographic consequences or remain purely of number-theoretic interest.