number.wiki

number.wiki

A wiki of numbers. Properties, factorizations, sequences, and curated context for every notable integer — currently 11,382 pages and growing.

Any non-negative integer works. Notable numbers get a permanent page; others show a live analysis.

Try /42, /1729, or /2026.

Popular tags

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Curated 27 Prime 9,594 Fibonacci 18 Perfect Number 3 Palindrome 203 Happy Number 1,718 Power of Two 12 Carmichael Number 3

From the wiki

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Greek numerals
The Milesian system that turned the alphabet into numbers, with distinct letters for ones, tens, and hundreds.
Jun 28, 2026
Roman numerals
The additive-subtractive letter system — I, V, X, L, C, D, M — still on clock faces, book chapters, and movie credits.
Jun 26, 2026
Triangular numbers
1, 3, 6, 10, 15 … the counting numbers stacked into triangles, and Gauss's famous shortcut for summing them.
Jun 20, 2026

Featured

0
0 — Zero
1
1 — One
2
2 — The Only Even Prime
3
3 — Three
7
7 — Seven
13
13 — Thirteen
17
17 — Seventeen
23
23 — Twenty-Three
42
42 — The Answer to Life, the Universe, and Everything
60
60 — Sexagesimal Base
69
69 — Sixty-Nine
100
100 — One Hundred