98

Number
$98$ (ninety-eight) is:


 * $2 \times 7^2$


 * The $13$th nontotient after $14$, $26$, $34$, $38$, $50$, $62$, $68$, $74$, $76$, $86$, $90$, $94$:
 * $\nexists m \in \Z_{>0}: \phi \left({m}\right) = 98$
 * where $\phi \left({m}\right)$ denotes the Euler $\phi$ function


 * The $1$st of the $3$rd pair of consecutive integers which both have $6$ divisors:
 * $\tau \left({98}\right) = \tau \left({99}\right) = 6$


 * The $5$th even integer after $2, 4, 94, 96$ that cannot be expressed as the sum of $2$ prime numbers which are each one of a pair of twin primes.


 * The $1$st even integer that cannot be expressed as the sum of $2$ prime numbers of which the smaller one is $3$, $5$ or $7$.


 * With $89$, gives the longest reverse-and-add sequence of any $2$-digit integers, of $24$ terms.


 * The $19$th positive integer $n$ after $5, 11, 17, 23, 29, 30, 36, 42, 48, 54, 60, 61, 67, 73, 79, 85, 91, 92$ such that no factorial of an integer can end with $n$ zeroes.

Also see

 * 2-Digit Numbers forming Longest Reverse-and-Add Sequence
 * Reciprocal of 98