∞ Crazy Numbers

The infinite
universe of numbers

Mathematical properties, cultural meanings, representations and curiosities of every number.

∞
Primes (1–100)
25
Primes (1–100)
4
Perfect (1–1000)
15
Fibonacci (1–1000)
4
Languages
Quick access
🔢
Browse by range
Click on a number to discover all its mathematical properties.
 📊
Multiplication Tables
Interactive tables from 1 to 20
 🧮
Math Exercises
Train your brain with random exercises!
 ✨
Number of the Day
Discover number 15
Categories
👑
Prime numbers
2, 3, 5, 7, 11, 13…
 💎
Perfect numbers
6, 28, 496, 8128…
 🌀
Fibonacci sequence
1, 1, 2, 3, 5, 8, 13, 21…
 🔁
Palindromes
11, 22, 121, 131…
Famous Numbers
0
Nothingness
1
The base
2
Only even prime
3
Triangle & trinity
5
Symbol of life
7
The lucky one
12
Twelve apostles
13
Unlucky
42
Ultimate answer
100
The century
360
Degrees in a circle
666
Number of the Beast