Solution: 72=8×9, which means that this number is an even number divisible by 9, the last three digits are multiples of 8, and the last two digits are multiples of 4.

At 123456789. 456 is a multiple of 8, but 123456 is not a multiple of 9;

101121314 161718,/kloc-0. It is (1+2+3+4+5+6+7+8+9)+(1+0)+(1+)+(1+2) = 5655.

In 202 12223242526272829, the multiple of 4 is 20, 24, 28, of which 920,728 is a multiple of 8, but (1+23+... 9)+(1+65438+)

In 303 13233343536373839, the multiple of 4 is 32,36, of which 536 is the multiple of 8, (1+1+65438+1+2+...+65433.

So when writing the natural number 36, you can divide the long number by 8 and 9 at the same time for the first time.

A: This natural number is 36.