What are the major factors that influence LogP The partition coefficient is a very useful metric in characterizing compounds particularly drugs. What chemical properties influence that partitioning? Are chemical moieties additive in their LogP? What if the compound has both hydrophobic and hydrophilic ends?
Partition Coefficient, represented as P and defined as: P = [Organic phase] / [Aqueous phase] 

Where "[]" represents concentration in the  phase and $\mathrm{\log (P)= \log_{10}(Partition Coefficient)}$ if log P value is higher then its more lipophilic ;those drugs were more absorbed by cells and elimination of those drugs from body will be less .The partition coefficient is a ratio of concentrations of un-ionized compound between the two solutions so for a chemical which is having both hydrophobic and hydrophilic ends also have log P values.

Eg: Oleic acid: $\mathrm{\log (P)= 7.64}$

chemicals which are hydrophopic(lipophilic) tends to have more Log P values and hydrophilic(lipophobic) chemicals have less log P.

eg: pentane($\mathrm{\log (P)= 3.45}$) [lipohilic], 1-pentanol ($\mathrm{\log (P)= 1.51}$) [lipophobic]