integer
number that can be written without a fractional or decimal component
natural number
number in the set of natural numbers, used for counting
process identifier
number to identify each process running on a computer
Friedman number
integer expressible as an arrangement of its digits with simple mathematical operations
Fibonacci number
integer in the infinite Fibonacci sequence
intersection number
generalized notion of counting curve intersections
characteristic
in a field or a ring, the smallest positive integer, if any, such that the sum of n ones equals 0; zero otherwise
self number
a natural number that cannot be written as the sum of any other natural number n and the individual digits of n
Skewes' number
number
zero
integer number zero; neutral element for the addition
cyclic number
integer whose multiples are digit permutations
Carol number
a number whose binary representation is almost all ones, with a zero in the central bit position
Miller index
describing crystal lattice planes
Euler number
integer sequence defined by the Taylor series expansion of the hyperbolic secant function and also appearing in that of the secant function
powerful number
integer where each prime number dividing it can be squared to still divide it
lucky numbers of Euler
class of natural numbers
relative dimension
difference between two dimensions
odd number
integer not divisible by two
divisor
integer that wholly divides another integer
almost perfect number
natural number whose proper divisors sum to one less than itself
Markov number
an integer x, y, or z that can solve the Markov equation x^2 + y^2 + z^2 = 3xyz
even number
integer divisible by two
harmonic number
sum of the first n whole number reciprocals; 1/1 + 1/2 + 1/3 + ... + 1/n
signed zero
zero with an associated sign
Keith number
integer that appears as a term in a linear recurrence relation with initial terms based on its own digits
Pell number
denominator of close rational approximation to the square root of 2