How do you say 26 digit number?

Answer 1

Such numbers are best written - and pronounced - in scientific notation. Normally you don't need all the digits, so you can round such a number to an appropriate number of significant digits - for example, 25670000..... Then you express it in scientific notation, in this example, 2.567 x 1025.

Edit:

I agree entirely with the previous answer but, if you must:

The 2-digit name for digits 1-2 followed by "septillion",

the 3-digit name for digits 3-5 followed by "sextillion",

the 3-digit name for digits 6-8 followed by "quintillion",

the 3-digit name for digits 9-11 followed by "quadrillion",

the 3-digit name for digits 12-14 followed by "trillion",

the 3-digit name for digits 15-17 followed by "billion",

the 3-digit name for digits 18-20 followed by "million",

the 3-digit name for digits 21-23 followed by "thousand", and

the 3-digit name for digits 24-26.