221221012 has 6 divisors (see below), whose sum is σ = 387136778. Its totient is φ = 110610504.

The previous prime is 221220997. The next prime is 221221037. The reversal of 221221012 is 210122122.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 204947856 + 16273156 = 14316^2 + 4034^2 .

It is a junction number, because it is equal to n+sod(n) for n = 221220983 and 221221001.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27652623 + ... + 27652630.

Almost surely, 2^221221012 is an apocalyptic number.

It is an amenable number.

221221012 is a deficient number, since it is larger than the sum of its proper divisors (165915766).

221221012 is a wasteful number, since it uses less digits than its factorization.

221221012 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55305257 (or 55305255 counting only the distinct ones).

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

The square root of 221221012 is about 14873.5003277641. The cubic root of 221221012 is about 604.7958348502.

Adding to 221221012 its reverse (210122122), we get a palindrome (431343134).

The spelling of 221221012 in words is "two hundred twenty-one million, two hundred twenty-one thousand, twelve".