561340

Appears in sequences

• Numbers k such that phi(k) = sigma(core(k)) where phi(k) is the Euler totient function, sigma(k) the sum of divisors of k and core(k) the squarefree part of k (the smallest integer such that k*core(k) is a square).at n=28A069552
• Numbers n such that sigma(n) = 7*phi(n).at n=28A136540