They are members of an infinite set of numbers of the form 4000*k where k is an integer.
There are an infinite number of them.The smallest ten are:4,0008,00012,00016,00020,00024,00028,00032,00036,00040,000
The multiples of 1,000 are an infinite number of integers in the set that begins 1000, 2000, 3000, 4000, and so on.
1000, 2000, 3000, 4000, 5000
800, 1600, 2400, 3200, 4000, 4800, 5600, . . .
Since 1000 is even, all of its multiples are even as well. Simply multiply 1000 by different integers, to gets its multiples.
500, 1000, 1500, 2000, 2500, 3000, 3500, 4000, 4500, 5000, 5500, . . .
2000, 4000, 6000, 8000, 10000, 12000, 14000, 16000, . . .
They are: 500 1000 1500 2000 2500 3000 3500 4000 4500 and 5000
3100 3200 3300 3400 3500 3600 3700 3800 3900
They are 500, 1000, 1500, 2000, 2500, 3000, 3500, 4000, 4500, and 5000.
800, 1600, 2400, 3200, 4000, 4800, 5600, 6400, 7200, 8000, 8800, 9600, 10400, . . .
800, 1600, 2400, 3200, 4000, 4800, 5600, 6400, 7200, 8000, 8800, 9600, 10400, 11200, 12000.