Here's how we get there:

1. Move the decimal point to the left until there is only one non-zero digit to the left of the decimal. In this case, we move it 15 places to the left: 3.356

2. Count the number of places you moved the decimal. This number becomes the exponent of 10. In this case, we moved it 15 places, so the exponent is 15.

3. Combine the number (3.356) with the power of ten (10¹⁵) to get the scientific notation: 3.356 x 10¹⁵.