267

Number

$267$ (two hundred and sixty-seven) is:

$3 \times 89$

The $50$th lucky number:

$1$, $3$, $7$, $9$, $13$, $15$, $21$, $\ldots$, $219$, $223$, $231$, $235$, $237$, $241$, $259$, $261$, $267$, $\ldots$

The $1$st term of the smallest triplet of integers in arithmetic sequence which have the same divisor sum:

$\map {\sigma_1} {267} = \map {\sigma_1} {295} = \map {\sigma_1} {323} = 360$

The length of the longest face diagonal of the smallest cuboid whose edges and the diagonals of whose faces are all integers:

The lengths of the edges are $44, 117, 240$

The lengths of the diagonals of the faces are $125, 244, 267$.

1997: David Wells: Curious and Interesting Numbers (2nd ed.) ... (previous) ... (next): $267$