90vertigo

See that $a^2 = c^2-b^2$ .

$\therefore 857^2 = (c+b)(c-b)$

But as $b,c$ are positive integers, none of them is zero, and $857$ is a prime number.

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Hence the only way in which we can factorize the number $857^2$ into two different integer factors, is $857^2 \times 1$

$\therefore$ $c+b= 857^2=734449 ,\\ c-b =1$

$\therefore b=367224 , c=367225$

Required answer is $2c+bc = c(2+b) = 367225\times 367226 = \boxed{134854567850}$