Largest prime factor: Difference between revisions
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<br>What is the largest prime factor of the number 600851475143 ?
<br><br>
=={{header|C}}==
<lang c>#include <stdio.h>
#include <stdlib.h>
int isprime( long int n ) {
int i=3;
if(!(n%2)) return 0;
while( i*i < n ) {
if(!(n%i)) return 0;
i+=2;
}
return 1;
}
int main(void) {
long int n=600851475143, j=3;
while(!isprime(n)) {
if(!(n%j)) n/=j;
j+=2;
}
printf( "%ld\n", n );
return 0;
}</lang>
{{out}}<pre>6857</pre>
=={{header|Fermat}}==
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