Writing of integers: from high to low, writing step by step. If there is no unit on any number, write 0 on the number and write accordingly.

Rounding to 100 million digits means rounding the digits after 100 million digits, and then writing "100 million words" after the digits.

1 504,760,000 Writing:1504,760,000, rounded to hundreds of millions is150,000.

So the answer is: 1504760000,1500 million.

This topic mainly examines the writing, rewriting and divisor of integers, and pays attention to the need to bring counting units when rewriting and divisor.