A scientific, encyclopedic, collaborative database of numbers.
The searchbar can be used to search for:

Enter the number in one of three formats:

Decimal representation including the period,
e.g. "3.14" to search for pi.
The search will be done in an interval around the entered number:
Entering "3.14" will search for numbers in the interval (3.13, 3.15).

Scientific notation (no period necessary),
e.g. "14e2" to search numbers between 1300 and 1500.

NumberDB's pnotation:
Enter a term of the form "ApB", where A and B are integers.
It corresponds to the number 10^{A} · 0.B, e.g. "1p314" for pi.
The sign of the number is determined by the sign of B.

Enter the first few digits after the period, e.g. "1415" for pi.

Enter the exact integer without period, e.g. "1".
This works for integers with up to 127 binary digits (roughly 38 decimal digits).
For longer integers,
try to search them as real numbers.

Enter sums or differences of the form "A" or "i*A" or "A*i", where "A" is a
real number in the above format
or a rational number.
Entering "1/2 + i * 0.86602" (to search for a third root of unity) will
search within a larger square around it.
Both, real and imaginary parts need sufficient precision.

Search for numbers in $\mathbb{Q}_p$ in one of two formats:

Enter "Q2:1010" to search for $2^0 + 2^2 + O(2^5)$.
Enter "Q2:1.1010" to search for $2^{1} + 2^0 + 2^2 + O(2^5)$.
For $p>10$, any $p$adic digit needs to be given in base 10 with the same number of base 10 letters as $p$,
e.g. "Q13:0102" will search for $13$adic numbers of the form $1+2\cdot 13 + O(13^2)$.
Minus signs are also interpreted, e.g. "Q3:220" searches for $(2 + 2\cdot 3^1) + O(3^3)$.

Enter "3 + O(2^5)" or "2^0+2^1+O(2^5)" for numbers of the form $2^0 + 2^2 + O(2^5)$.
This format also works for $\mathbb{Q}_p$, e.g. enter "3/5 + O(5^1)".

Enter polynomials over $\mathbb{Q}$ in arbitrary variables,
e.g. enter "x^6+y^6x^5*y^5+4*x*y" to search for $x^6+y^6x^5y^5+4xy$.

Enter words from the table's title, keywords, tags, definition, or comments.

Enter the first letters of one word of a tag, e.g. "irr" for the tag "Irrational".