6591375

Appears in sequences

• A unitary phi reciprocal amicable number: consider two different numbers r, s which satisfy the following equation for some integer k: uphi(r) = uphi(s) = (1/k) * r * s / (r-s); or equivalently, 1/uphi(r) = 1/uphi(s) = k * (1/s - 1/r); sequence gives r numbers.at n=33A080766
• Numbers k such that both k and k+1 are nonunitary abundant numbers (A064597).at n=12A327942