FACTOR(1) General Commands Manual FACTOR(1)
factor, primes - factor a number, generate large primes
factor [ number ]
When factor is invoked without an argument, it waits for a number to be
typed in. If you type in a positive number less than 256 (about
7.2e16) it will factor the number and print its prime factors; each one
is printed the proper number of times. Then it waits for another num-
ber. It exits if it encounters a zero or any non-numeric character.
If factor is invoked with an argument, it factors the number as above
and then exits.
Maximum time to factor is proportional to sqrt(n) and occurs when n is
prime or the square of a prime. It takes 1 minute to factor a prime
near 1014 on a PDP11.
When primes is invoked, it waits for a number to be typed in. If you
type in a positive number less than 256 it will print all primes
greater than or equal to this number.
`Ouch.' for input out of range or for garbage input.