title: Exploding a number and separate it by a space
body: <p>I want to explode a string or an integer and separate it by a space. </p>
  
  <p>E.g., I have this int <strong>12345678</strong>, and I want its numbers to become like <strong>123 45678</strong>. I want the first three numbers separated. Can someone give me a clue or hint in how to achieve this, like what function to use in PHP? I think using an <code>explode</code> will not work here because the <code>explode</code> function needs a separator.</p>