221021212 has 6 divisors (see below), whose sum is σ = 386787128. Its totient is φ = 110510604.

The previous prime is 221021197. The next prime is 221021221. The reversal of 221021212 is 212120122.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 221021192 and 221021201.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27627648 + ... + 27627655.

Almost surely, 2^221021212 is an apocalyptic number.

It is an amenable number.

221021212 is a deficient number, since it is larger than the sum of its proper divisors (165765916).

221021212 is a wasteful number, since it uses less digits than its factorization.

221021212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55255307 (or 55255305 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 13.

The square root of 221021212 is about 14866.7821669654. The cubic root of 221021212 is about 604.6137023543.

Adding to 221021212 its reverse (212120122), we get a palindrome (433141334).

The spelling of 221021212 in words is "two hundred twenty-one million, twenty-one thousand, two hundred twelve".