Nothing to do with Google.

(Apologies if this is pedantic, but:)

The letter "e" (for "exponent") has meant "multiplied by ten to the power of", since the dawn of computing (Fortran!), when it was impossible to display or type a superscripted exponent.

In computing, we all got used to it because there was no other available notation (this is also why we use * for multiplication, / for division, etc). And it's intuitive enough, if you already know scientific notation, which Fortran programmers did.

Scientific notation goes back even further, and is used when the magnitude of the number exceeds the available significant digits.

E.g., Avogadro's number is 6.02214076 × 10⁻²³. In school we usually used it as 6.022 × 10⁻²³, which is easier to work with and was more appropriate for our classroom precision. In E notation, that'd be 6.022E-23.

1.3076744e+12 is 1.3076744 × 10¹². The plus sign is for the positive exponent, not addition. You could argue that the plus sign is redundant, but the clear notation can be helpful when working with numbers that can swing from one to the other.