Adding to 21225212 its reverse (21252212), we get a palindrome (42477424).
Subtracting 21225212 from its reverse (21252212), we obtain a cube (27000 = 303).
It is a congruent number.
It is an unprimeable number.
Almost surely, 221225212 is an apocalyptic number.
It is an amenable number.
21225212 is a wasteful number, since it uses less digits than its factorization.
21225212 is an evil number, because the sum of its binary digits is even.
The square root of 21225212 is about 4607.0828080251. The cubic root of 21225212 is about 276.8751712874.
The spelling of 21225212 in words is "twenty-one million, two hundred twenty-five thousand, two hundred twelve".