66433720320
domain: N
Appears in sequences
- Multiply-perfect numbers: n divides sigma(n).at n=23A007691
- 4-perfect (quadruply-perfect or sous-triple) numbers: sum of divisors of n is 4n.at n=8A027687
- Multiply perfect numbers that are also harmonic numbers but are not arithmetic numbers.at n=10A046986
- Numbers k whose average divisor is nonintegral and divides k.at n=22A046999
- Numbers m such that m = sigma(abs(k)) - 3k, where k = sigma(m) - 3m.at n=16A069146
- Numbers k such that sigma(k)/k, sigma_3(k)/k and sigma_5(k)/k are all integers.at n=14A076231
- Numbers k such that sigma(k)/k and sigma_3(k)/k are both integers.at n=17A076233
- Multiply perfect numbers k for which the quotient sigma_7(k)/k = A013955(k)/k is nonintegral.at n=2A088846
- Multiply perfect numbers k such that sigma(k)/k > 2.at n=16A166069
- Multi-perfect numbers m from A007691 such that m*(m-tau(m))/sigma(m) is an integer h, where k-tau(k) is the number of nondivisors of k (A049820) and sigma(k) is the sum of the divisors of k (A000203).at n=17A325023
- Numbers that are multi-perfect (A007691) and simultaneously harmonic (A001599).at n=19A325025
- Numbers k for which gcd(2k, sigma(k)) = 2k.at n=14A325637
- Multiply-perfect numbers m whose average divisor is not an integer.at n=14A330533
- Numbers whose abundancy index is a power of 2.at n=15A336702
- Numbers k such that both sigma_{-1}(k) > 2 and sigma_0(k)/sigma_{-1}(k) are integers.at n=12A340864
- Multiply-perfect numbers k that have a divisor d such that sigma(d)*d = k.at n=15A348031
- Multiply-perfect numbers that are the sum of the divisors of some number.at n=22A354073
- Multiperfect numbers k for which gcd(k,A003961(k))*gcd(sigma(k),A276086(k)) is equal to gcd(k,A276086(k))*gcd(sigma(k),A003961(k)), where A003961(n) is fully multiplicative with a(prime(i)) = prime(i+1), and A276086 is the primorial base exp-function.at n=17A379491