| FACTOR(6) | Games Manual | FACTOR(6) | 
factor —
| factor | [ -h] [number ...] | 
factor utility factors integers larger than 1. When
  a number is factored, it is printed, followed by a “:”, and the
  list of (prime) factors on a single line. Factors are listed in ascending
  order, and are preceded by a space. By default, if a factor divides a value
  more than once, it will be printed more than once.
When factor is invoked with one or more
    number arguments, each argument will be factored.
When factor is invoked with no
    number arguments, factor reads
    numbers, one per line, from standard input, until end of file or error.
    Leading white-space and empty lines are ignored. Numbers may be preceded by
    a single +. Integer less than 2 are rejected. Numbers are terminated by a
    non-digit character (such as a newline). After a number is read, it is
    factored. Input lines must not be longer than LINE_MAX -
    1 (currently 2047) characters.
By default, factor is compiled against the
    OpenSSL bignum implementation
    openssl_bn(3), which lets
    it handle arbitrarily large values. (Note however that very large values can
    take a very long time to factor.) If factor is
    compiled without OpenSSL it is limited to the maximum value of
    unsigned long.
The following option is available:
-h-h flag is specified, factors will be
      printed in "human-readable" format. If a factor x divides a
      value n (>1) times, it will appear as x^n.| Nov 12, 2017 | NetBSD 9.2 |