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Kim Kardashian

Kim Kardashian thinks four is the "magic number" when it comes to having children.

The 38-year-old reality star and her husband, Kanye West, welcomed their fourth child, son Psalm, via surrogate in May. And the latest addition to the star's brood, which also includes son Saint, three and daughters North, six, and 19-month-old Chicago, has made her family "perfect."

"I feel like having four is so much more zen," she told Entertainment Tonight. "I feel really calm and zen. I feel like they all love each other.

"My two older kids would fight a little bit and now, since the baby's here, everyone gets along, everyone loves each other. I'm rolling with it. It just really is zen. It feels really equal and calm and great."

The Keeping Up with the Kardashians star went on to suggest she's reluctant to have any more children, adding: "Because I am so busy doing so many other things, I want to make sure each kid gets so much of my attention.

"It's so important to give the perfect amount of attention to every kid, especially with school now and with everything that I'm doing. I really just can't extend myself beyond this. Everyone always asks, 'What's next?' And I'm like, 'I'm just going to focus and do what I'm doing.' I can't do anything else."

But Kim joked if she was to have more kids, she'd have to have two - because she only wants even numbers.

"I would do even numbers, so I could go two more, but I won't, I won't. I think that's just like, I think I'll go crazy," she laughed. "But I think four is the perfect, magic number for me."