101

Number
$101$ (one hundred and one) is:


 * The $26$th prime number


 * The $1$st of the $9$th pair of twin primes, with $103$


 * The $6$th palindromic prime after $2, 3, 5, 7, 11$.


 * The $7$th of $29$ primes of the form $2 x^2 + 29$:
 * $2 \times 6^2 + 29 = 101$


 * The $50$th positive integer after $2, 3, 4, 7, 8, \ldots, 61, 65, 66, 67, 72, 77, 80, 81, 84, 89, 94, 95, 96, 100$ which cannot be expressed as the sum of distinct pentagonal numbers.