205031221 has 2 divisors, whose sum is σ = 205031222. Its totient is φ = 205031220.

The previous prime is 205031209. The next prime is 205031227. The reversal of 205031221 is 122130502.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 204890596 + 140625 = 14314^2 + 375^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-205031221 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 205031195 and 205031204.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (205031227) by changing a digit.

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, 102515610 + 102515611.

It is an arithmetic number, because the mean of its divisors is an integer number (102515611).

Almost surely, 2^205031221 is an apocalyptic number.

It is an amenable number.

205031221 is a deficient number, since it is larger than the sum of its proper divisors (1).

205031221 is an equidigital number, since it uses as much as digits as its factorization.

205031221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 120, while the sum is 16.

The square root of 205031221 is about 14318.9113063808. The cubic root of 205031221 is about 589.6667858958. Note that the first 3 decimals are identical.

Adding to 205031221 its reverse (122130502), we get a palindrome (327161723).

The spelling of 205031221 in words is "two hundred five million, thirty-one thousand, two hundred twenty-one".