Adding to 13213021 its reverse (12031231), we get a palindrome (25244252).
It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 12031231 = 23 ⋅523097.
It is a cyclic number.
It is a Duffinian number.
It is a congruent number.
Almost surely, 213213021 is an apocalyptic number.
It is an amenable number.
13213021 is an equidigital number, since it uses as much as digits as its factorization.
13213021 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 26978.
The square root of 13213021 is about 3634.9719393690. The cubic root of 13213021 is about 236.4108339987.
The spelling of 13213021 in words is "thirteen million, two hundred thirteen thousand, twenty-one".