EntityQ915474· pop 23· linked from 315 articlesdivisor functionSign in to savearithmetic function related to the divisors of an integerConnectionsdivisorEntityprime numberEntitySrinivasa RamanujanEntityabundant numberEntityEuler's totient functionEntitybig O notationEntityAmerican Mathematical MonthlyEntityRamanujan's sumEntityJeffrey LagariasEntitymathematicsEntityLeonhard EulerEntityInternational Standard Book NumberEntitynatural numberEntitycomplex numberEntityintegerEntitynumber theoryEntitydigital object identifierEntityInternational Standard Serial NumberEntityexponentiationEntityG.H. HardyEntityCategoriesAnalytic number theoryDivisor functionNumber theoryZeta and L-functions