205240121 has 2 divisors, whose sum is σ = 205240122. Its totient is φ = 205240120.

The previous prime is 205240093. The next prime is 205240127. The reversal of 205240121 is 121042502.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 138980521 + 66259600 = 11789^2 + 8140^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-205240121 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 205240121.

It is not a weakly prime, because it can be changed into another prime (205240127) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 102620060 + 102620061.

It is an arithmetic number, because the mean of its divisors is an integer number (102620061).

Almost surely, 2^205240121 is an apocalyptic number.

It is an amenable number.

205240121 is a deficient number, since it is larger than the sum of its proper divisors (1).

205240121 is an equidigital number, since it uses as much as digits as its factorization.

205240121 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 160, while the sum is 17.

The square root of 205240121 is about 14326.2039982683. The cubic root of 205240121 is about 589.8669823657.

Adding to 205240121 its reverse (121042502), we get a palindrome (326282623).

The spelling of 205240121 in words is "two hundred five million, two hundred forty thousand, one hundred twenty-one".