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.


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

Also see

 * 2-Digit Numbers forming Longest Reverse-and-Add Sequence