221205412 has 24 divisors (see below), whose sum is σ = 390846456. Its totient is φ = 109540608.

The previous prime is 221205409. The next prime is 221205431. The reversal of 221205412 is 214502122.

It can be written as a sum of positive squares in 4 ways, for example, as 137921536 + 83283876 = 11744^2 + 9126^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 221205412.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 257688 + ... + 258544.

It is an arithmetic number, because the mean of its divisors is an integer number (16285269).

Almost surely, 2^221205412 is an apocalyptic number.

It is an amenable number.

221205412 is a deficient number, since it is larger than the sum of its proper divisors (169641044).

221205412 is a wasteful number, since it uses less digits than its factorization.

221205412 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1407 (or 1405 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 19.

The square root of 221205412 is about 14872.9758958992. The cubic root of 221205412 is about 604.7816182428.

Adding to 221205412 its reverse (214502122), we get a palindrome (435707534).

The spelling of 221205412 in words is "two hundred twenty-one million, two hundred five thousand, four hundred twelve".