4563000

Appears in sequences

• Numbers k such that phi(k) + sigma(k) = 4*k.at n=3A011254
• Nonprimes k that divide sigma(k) + phi(k).at n=15A011774
• Numbers n such that (phi(n) + sigma(n))/(rad(n))^2 is an integer > 1 (phi=A000010, sigma=A000203, rad=A007947).at n=23A097982
• Numbers k such that (phi(k) + sigma(k))/rad(k)^2 is an integer, that is (phi(k) + sigma(k)) is divisible by every prime factor of k squared.at n=25A121850
• a(n) = Product_{d|n, d<n} prime(A286622(d)-1).at n=59A305792