Katrillion vs. Quadrillion — What's the Difference?

An unspecified large number (of).

The cardinal number equal to 1015.

Chiefly British The cardinal number equal to 1024.

A thousand trillion ([https://en.wikipedia.org/wiki/Long_and_short_scales#Comparison logic: 1,000 × 1,000^4]): 1 followed by fifteen zeros, 10¹⁵.

A million trillion ([https://en.wikipedia.org/wiki/Long_and_short_scales#Comparison logic: 1,000 × 1,000,000^2]): 1 followed by twenty-four zeros, 10²⁴.

Any very large number, exceeding normal description.

According to the French notation, which is followed also upon the Continent and in the United States, a unit with fifteen ciphers annexed; according to the English notation, the number produced by involving a million to the fourth power, or the number represented by a unit with twenty-four ciphers annexed. See the Note under Numeration.

The number that is represented as a one followed by 24 zeros;

The number that is represented as a one followed by 15 zeros