Welcome to the Number Dictionary!
This website is an informational resource for the fascinating properties of numbers and numeral systems.
New Features: Duodecimal & Vigesimal systems, Negabinary, Nonagonal/Decagonal numbers, Perfect powers, Abundant/Deficient numbers, Twin primes, Harshad, Kaprekar, and Smith numbers!
Representation numerals
Greek
Arabic
Roman
Maya
Chinese
Hebrew
Numeral systems
Binary
Base-3
Base-4
Base-5
Base-6
Septimal
Octal
Duodecimal
Hexadecimal
Vigesimal
Base-24
Base-36
Negabinary
Multi-Polygonal numbers
Triangular
Square
Pentagonal
Hexagonal
Heptagonal
Octogonal
Nonagonal
Decagonal
Special numbers
Primes
Twin primes
Gaussian primes
Fibonacci
Perfect numbers
Abundant numbers
Deficient numbers
Palindromic
Layland
Harshad
Kaprekar
Smith
Sums & other
Difference of 2 squares
Sum of all divisors
Divisors
Factorization
Perfect powers
Begin with a random number: 61, or use the search on the top.