How many significant figures are there in the number 37,460,000?

Count from the first non-zero digit to the last non-zero digit. In 37,460,000 these are 3, 7, 4, 6, which is 4 digits.

The zeros at the end only show the size of the number. They are place-holders, not measured digits, so they are not significant.

So there are 4 significant figures. In standard form, 3.746 × 10⁷ shows this clearly.