Pendra was the only withdrawal on Thursday, leaving Doctor Harper as the last horse to make the cut.
Vieux Lion Rouge and Definitly Red are the bookmakers’ favourites, at about 10-1, for the famous race.
Coverage of the National, over 30 fences and more than four and a quarter miles, is said to be followed by 600 million people worldwide.
The National is a handicap chase, with each runner allotted a different weight to carry by the official handicapper Phil Smith.
With 11st 10lb, The Last Samuri will bid to become the first top-weight to triumph since the legendary Red Rum in 1974.
Terminally ill five-year-old boy Bradley Lowery is to be given honorary 41st place in the National racecard.
Armed police will be in attendance at the course as the three-day meeting gets under way on Thursday.
This year’s race comes in the wake of the Westminster terror attack and marks the 20th anniversary of the National being delayed by an IRA bomb scare.
Merseyside Police Commander, Chief Superintendent Claire Richards, said: “Racegoers can expect to see high visibility policing across the three days of the event.
“They may also see an armed presence but I want to reassure them that this is not in response to any direct threat aimed at the festival but just as a visible reassurance for the thousands of people who will come through the gates over the three days.”