Mathematicians are an odd bunch. Names for just about everyhing. There are amicable numbers and perfect number, sociable number and betrothed numbers. There are sublime number, frugal number, and quasiperfect number. Heck, there are powerful number, smooth number, and even sphenic numbers. Rather a lot to deal with all told… So let’s just focus on two of them: perfect numbers and amicable numbers.