0

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Number

$0$ (zero) is:


The only number which is both positive and negative


The only integer which is divisible by $0$


The only integer which is divisible by all integers


The identity element for the operation of addition


The zero element for the operation of multiplication


The value of $\log_b 1$ for all bases $b$


The $0$th (and therefore smallest) cardinal number


The $0$th (and therefore smallest) ordinal number


The $0$th Fibonacci number


The $0$th square number:
$0 = 0^2$


The $0$th triangular number:
$0 = \dfrac {0 \paren {0 + 1} } 2$


The $0$st number to be both square and triangular:
$0 = 1^0 = \dfrac {0 \times \paren {0 + 1} } 2$


The $0$th square which has no more than $2$ distinct digits and does not end in $0$:
$0 = 0^2$


The $1$st subfactorial:
$0 = 1! \paren {1 - \dfrac 1 {1!} }$


The $1$st integer $m$ such that $m! + 1$ (its factorial plus $1$) is prime:
$0! + 1 = 1 + 1 = 2$


The $1$st integer such that its double factorial plus $1$ is prime:
$0!! + 1 = 2$


The $1$st integer $n$ such that $2^n$ contains no zero in its decimal representation:
$2^0 = 1$


The $1$st integer $n$ such that $5^n$ contains no zero in its decimal representation:
$5^0 = 1$


The $1$st integer $n$ such that both $2^n$ and $5^n$ have no zeroes:
$2^0 = 1, 5^0 = 1$


The $1$st integer which is palindromic in both decimal and binary:
$0_{10} = 0_2$


The $1$st integer which is palindromic in both decimal and ternary:
$0_{10} = 0_3$


The $1$st number which is (trivially) the sum of the increasing powers of its digits taken in order:
$0^1 = 0$


The $1$st integer $m$ such that $m^2 = \dbinom n 0 + \dbinom n 1 + \dbinom n 2 + \dbinom n 3$ for integer $n$:
$0^2 = \dbinom {-1} 0 + \dbinom {-1} 1 + \dbinom {-1} 2 + \dbinom {-1} 3$


The $1$st of the $5$ Fibonacci numbers which are also triangular


The $1$st palindromic triangular number


The $1$st palindromic integer which is the index of a palindromic triangular number
$T_0 = 0$


The $1$st palindromic integer whose square is also palindromic integer
$0^2 = 0$


The $1$st Ramanujan-Nagell number:
$0 = 2^0 - 1 = \dfrac {0 \paren {0 + 1} } 2$


The $1$st of the $3$ Fibonacci numbers which equals its index


The $1$st Dudeney number:
$0^3 = 0$


The $1$st non-negative integer $n$ such that the Fibonacci number $F_n$ ends in $n$


The $1$st of the $6$ integers which are the middle term of a sequence of $5$ consecutive integers whose cubes add up to a square:
$\paren {-2}^3 + \paren {-1}^3 + 0^3 + 1^3 + 2^3 = 0 = 0^2$


The $1$st of the only $2$ integers which are equal to the sum of the squares of their digits when expressed in base $10$:
$0 = 0^2$


The $2$nd integer $n$ after $-1$ such that $\dbinom n 0 + \dbinom n 1 + \dbinom n 2 + \dbinom n 3 = m^2$ for integer $m$:
$\dbinom 0 0 + \dbinom 0 1 + \dbinom 0 2 + \dbinom 0 3 = 1^2$


Also see


Previous in sequence: $-1$


Next in sequence: $1$


Historical Note

The Babylonians from the $2$nd century BCE used a number base system of arithmetic, with a placeholder to indicate that a particular place within a number was empty, but its use was inconsistent. However, they had no actual recognition of zero as a mathematical concept in its own right.


The Ancient Greeks had no conception of zero as a number.


The concept of zero was invented by the mathematicians of India. The Bakhshali Manuscript from the $3$rd century CE contains the first reference to it.


However, even then there were reservations about its existence, and misunderstanding about how it behaved.

In Ganita Sara Samgraha of Mahaviracharya, c. $850$ CE appears:

A number multiplied by zero is zero and that number remains unchanged which is divided by, added to or diminished by zero.


It was not until the propagation of Arabic numbers, where its use as a placeholder made it important, that it became commonplace.


Linguistic Note

The Sanskrit word used by the early Indian mathematicians for zero was sunya, which means empty, or blank.

In Arabic this was translated as sifr.

This was translated via the Latin zephirum into various European languages as zero, cifre, cifra, and into English as zero and cipher.


Note that the plural of zero is either zeros or zeroes. On $\mathsf{Pr} \infty \mathsf{fWiki}$, zeroes is preferred.


The word zero can also be used as a verb, meaning to set (a value) to zero in the context of algorithms and computer science

The word zeroize can also be seen in this context.


Sources

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