factor — Print prime factors
Print the prime factors of each number.The algorithm it uses is not very sophisticated, so for some inputs `factor’ runs for a long time.
$ factor 25 — Print prime factors
$ factor 125 200 — Print prime factors for each number.
$ factor `echo ‘2^64-1’|bc` — Factors the largest 64-bit number.
$ factor `echo ‘4294967279 * 4294967291’|bc` — Factors the largest 32-bit prime numbers. (Warning: It take more time)
Read: man factor