is-811-prime-number-or-no-

Question Number 166043 by mkam last updated on 12/Feb/22

i s 811 p r i m e n u m b e r o r n o ?

Commented by mahdipoor last updated on 12/Feb/22

y e s

Commented by mkam last updated on 12/Feb/22

h o w c a n y o u p r o v e t h i s

Commented by MJS_new last updated on 12/Feb/22

try to divide by all prime numbers ⩽ \sqrt{811}

\sqrt{811} = 28.47 \dots \Rightarrow you must try

2, 3, 5, 7, 11, 13, 17, 19, 23

Commented by alephzero last updated on 20/Feb/22

\sqrt{811} \approx 28

\Rightarrow 2 ∤ 811, 3 ∤ 811, 5 ∤ 811, 7 ∤ 811,

11 ∤ 811, 13 ∤ 811, 17 ∤ 811, 19 ∤ 811,

23 ∤ 811

\Rightarrow 811 is a prime number

Commented by naka3546 last updated on 12/Feb/22

811 n 881 are prime numbers .