These are the largest Mersenne numbers with no factors below 2^32 In NewPGen 2.82. There's about a 1 in a billion chance that one of them is prime: 2^(Prime Number)-1
Rank #	Equation	Digits
1	2^4,294,967,291-1	1,292,913,985
2	2^4294967279-1	1292913982
3	2^4294967231-1	1292913967
4	2^4294967197-1	1292913957
5	2^4294967189-1	1292913955
6	2^4294967161-1	1292913946
7	2^4294967143-1	1292913941
8	2^4294967111-1	1292913931
9	2^4294967087-1	1292913924
10	2^4294967029-1	1292913907
11	2^4294966997-1	1292913897
12	2^4294966981-1	1292913892
13	2^4294966943-1	1292913881
14	2^4294966927-1	1292913876
15	2^4294966909-1	1292913870
16	2^4294966877-1	1292913861
17	2^4294966829-1	1292913846
18	2^4294966813-1	1292913842
19	2^4294966769-1	1292913828
20	2^4294966667-1	1292913798
21	2^4294966661-1	1292913796
22	2^4294966657-1	1292913795
23	2^4294966651-1	1292913793
24	2^4294966639-1	1292913789
25	2^4294966619-1	1292913783
26	2^4294966591-1	1292913775
27	2^4294966583-1	1292913772
28	2^4294966553-1	1292913763
29	2^4294966477-1	1292913740
30	2^4294966447-1	1292913731
31	2^4294966441-1	1292913730
32	2^4294966427-1	1292913725
33	2^4294966373-1	1292913709
34	2^4294966367-1	1292913707
35	2^4294966337-1	1292913698
36	2^4294966297-1	1292913686
37	2^4294966243-1	1292913670
38	2^4294966237-1	1292913668
39	2^4294966231-1	1292913666
40	2^4294966217-1	1292913662
41	2^4294966187-1	1292913653
42	2^4294966177-1	1292913650
43	2^4294966163-1	1292913646
44	2^4294966153-1	1292913643
45	2^4294966129-1	1292913636
46	2^4294966121-1	1292913633
47	2^4294966099-1	1292913627
48	2^4294966087-1	1292913623
49	2^4294966073-1	1292913619
50	2^4294966043-1	1292913610
These were tested by Matt Stath in January 2013. Thanks to Paul Jobling, who developed NewPGen 2.82. Back to Top Secret Top 50 Primes.