Two Primes = A 400 digit number

It seems that any number with 300 or more digits seems very hard to get. How can I find two prime numbers that if multiplied, I'll get a 400 digit number?

100000929000001 * (2^1279 - 1) =
10408028884354591593
51465805683754600337
31896239083680656292
26432005396500315738
69961000470903971800
05285161232929230672
78085491011731825668
79138646005876890430
00738477599918129252
89474738359638417639
93017621142884424531
06799212965291026509
50864791348184303461
43522269271136681852
66159013266424636756
53730731056290654943
25888436080492240891
53424130264764090555
30399725712180111378
41863005024991729087