451

Number
$451$ (four hundred and fifty-one) is:


 * $11 \times 41$


 * The $6$th Fermat pseudoprime to base $4$ after $15$, $85$, $91$, $341$, $435$:
 * $4^{451} \equiv 4 \pmod {451}$


 * The smallest positive integer the decimal expansion of whose reciprocal has a period of $10$:
 * $\dfrac 1 {451} = 0 \cdotp \dot 00221 \, 7294 \dot 9$