It is a happy number.
It is a weak prime.
It is a cyclic number.
It is a congruent number.
Almost surely, 221213543315143 is an apocalyptic number.
21213543315143 is an equidigital number, since it uses as much as digits as its factorization.
21213543315143 is an odious number, because the sum of its binary digits is odd.
Adding to 21213543315143 its reverse (34151334531212), we get a palindrome (55364877846355).
The spelling of 21213543315143 in words is "twenty-one trillion, two hundred thirteen billion, five hundred forty-three million, three hundred fifteen thousand, one hundred forty-three".