even number
integer divisible by two
googol
large integer number defined as ten raised to the power of 100
googolplex
large number defined as ten to the power of one googol
perfect number
positive integer which equals the sum of all its divisors
zero
integer number zero; neutral element for the addition
Avogadro number
dimensionless number corresponding to Avogadro's constant (which has units of inverse mole)