Square Substring

Given a string $s$ consisting of digits $0-9$ only, find if it is possible to split the string into three parts such that the numerical value of the first and second substring is same and the value of the third substring is product of the value of first two strings. In other words add a single "$*$" and "$=$" sign in between the string such that it can be written as $a*a=a^2$ where $a$ represents