5517818880

Appears in sequences

• Nonunitary doubly perfect numbers: the sum of the nonunitary divisors of n is 2n; i.e., sigma(n) - usigma(n) = 2n.at n=10A064592
• Nontrivial nonunitary multiply perfect numbers: the sum of the nonunitary divisors of n is a positive multiple of n; i.e., (sigma(n) - usigma(n))/n is a positive integer.at n=17A064595
• Numbers k such that there is a proper divisor d of k satisfying sigma(d)=k.at n=17A081756
• Numbers n such that psi(n) is the sum of proper divisors of n where psi(n) = A001615(n).at n=8A291209
• Sum of divisors of the multiply-perfect numbers.at n=16A307741
• Numbers k such that s(k) = 4*k, where s(k) is the sum of divisors of k that have a square factor (A162296).at n=7A357494