Assuming interest is always a constant 5% there’s no advantage.
If all the money is put straight into the bank once received the future values are exactly the same.
With the lump sum payment the value of the payment will be 50,000,000 x ((1-(1/1.05^20)))/.05) x 1.05 = 654,266,042.98. After 19 years (when the 20th payment is made) the future value will be 654,266,042.98 x 1.05^19 = 1,653,297,705.14.
With the annuity option the year number, payment number, payment amount, present value at time 0 and value of the payment at time 19 (when the last payment is made) is as follows:
(Hope this copies from Excel nicely)
Time Payment # Payment Present Value at Time 0 Value at Time 19
0 1 50,000,000.00 50,000,000.00 126,347,509.77
1 2 50,000,000.00 47,619,047.62 120,330,961.68
2 3 50,000,000.00 45,351,473.92 114,600,915.89
3 4 50,000,000.00 43,191,879.93 109,143,729.42
4 5 50,000,000.00 41,135,123.74 103,946,408.97
5 6 50,000,000.00 39,176,308.32 98,996,579.97
6 7 50,000,000.00 37,310,769.83 94,282,457.12
7 8 50,000,000.00 35,534,066.51 89,792,816.30
8 9 50,000,000.00 33,841,968.10 85,516,967.91
9 10 50,000,000.00 32,230,445.81 81,444,731.34
10 11 50,000,000.00 30,695,662.68 77,566,410.80
11 12 50,000,000.00 29,233,964.45 73,872,772.19
12 13 50,000,000.00 27,841,870.91 70,355,021.13
13 14 50,000,000.00 26,516,067.53 67,004,782.03
14 15 50,000,000.00 25,253,397.65 63,814,078.13
15 16 50,000,000.00 24,050,854.90 60,775,312.50
16 17 50,000,000.00 22,905,576.10 57,881,250.00
17 18 50,000,000.00 21,814,834.38 55,125,000.00
18 19 50,000,000.00 20,776,032.74 52,500,000.00
19 20 50,000,000.00 19,786,697.85 50,000,000.00
Total 1,000,000,000.00 654,266,042.98 1,653,297,705.14
So either way, the future value at year 19 (when the 20th payment is made) with interest is 1,653,297,705.14.
Of course if the winner is a savvy investor that number could be significantly higher.
Is that what you were asking?