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: 122215 = 5 ⋅24443.
It is a cyclic number.
It is a Duffinian number.
512221 is a lucky number.
It is a congruent number.
2512221 is an apocalyptic number.
It is an amenable number.
512221 is a wasteful number, since it uses less digits than its factorization.
512221 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 512221 is about 715.6961645838. The cubic root of 512221 is about 80.0115087609.
Adding to 512221 its reverse (122215), we get a palindrome (634436).
The spelling of 512221 in words is "five hundred twelve thousand, two hundred twenty-one".