205231221 has 12 divisors (see below), whose sum is σ = 319248748. Its totient is φ = 126296064.

The previous prime is 205231151. The next prime is 205231223. The reversal of 205231221 is 122132502.

205231221 is a `hidden beast` number, since 20 + 523 + 122 + 1 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 57972996 + 147258225 = 7614^2 + 12135^2 .

It is not a de Polignac number, because 205231221 - 2²⁵ = 171676789 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 205231194 and 205231203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205231223) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 876940 + ... + 877173.

Almost surely, 2^205231221 is an apocalyptic number.

It is an amenable number.

205231221 is a deficient number, since it is larger than the sum of its proper divisors (114017527).

205231221 is a wasteful number, since it uses less digits than its factorization.

205231221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1754132 (or 1754129 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 205231221 is about 14325.8933752838. The cubic root of 205231221 is about 589.8584559431.

Adding to 205231221 its reverse (122132502), we get a palindrome (327363723).

The spelling of 205231221 in words is "two hundred five million, two hundred thirty-one thousand, two hundred twenty-one".