How many weapons are there in the U.S. nuclear arsenal?

""4,688 That's the latest estimate from Hans Kristensen at the Federation of American Scientists. If, like me, you don't have a security clearance, this is the closest we can get to an understanding of how many nuclear weapons the United States currently maintains in its arsenal: [T]he size of the stockpile is important because although the administration has declassified 64 years of its history, its current size is – yes, you guessed it – still a secret. In fact, officials have told us that the 2010 disclosure was a one-time decision, not something that would be updated each year. So all stockpile numbers after September 2009 are still secret. Deep in the dark corridors of the Pentagon there are still people who believe this is necessary for national security.""