569729160

Appears in sequences

• Smallest x such that sigma(x) = n*phi(x), or -1 if no such x exists.at n=27A055234
• a(n) = Min {x : sigma(x) = phi(n*x), x is not a prime}, least nonprime solutions to sigma(x) = phi(n*x).at n=27A087979
• a(n) = Min {x : sigma(x) = phi(n*x), x is not a prime}, least nonprime solutions to sigma(x) = phi(n*x).at n=28A087979
• a(n) = Min{x : sigma(x) = n*phi(x), x is not a prime}, the least nonprime solutions to sigma(x) = n*phi(x); special balanced numbers.at n=27A088830
• a(n) is the least number k > 0 such that sigma(k) = phi(n*k).at n=27A256527
• a(n) is the least number k > 0 such that sigma(k) = phi(n*k).at n=28A256527
• Numbers that are the product of 4 consecutive positive numbers and the product of 2 nontrivial oblong numbers.at n=8A276161
• Numbers of the form p^2-1 that have a record-breaking number of divisors, where p is prime.at n=25A323278
• Balanced numbers (A020492) k with a record value of sigma(k)/phi(k).at n=15A335287