205012121 has 2 divisors, whose sum is σ = 205012122. Its totient is φ = 205012120.

The previous prime is 205012097. The next prime is 205012141. The reversal of 205012121 is 121210502.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 111619225 + 93392896 = 10565^2 + 9664^2 .

It is a cyclic number.

It is not a de Polignac number, because 205012121 - 2²⁶ = 137903257 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 205012096 and 205012105.

It is not a weakly prime, because it can be changed into another prime (205012141) 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, 102506060 + 102506061.

It is an arithmetic number, because the mean of its divisors is an integer number (102506061).

Almost surely, 2^205012121 is an apocalyptic number.

It is an amenable number.

205012121 is a deficient number, since it is larger than the sum of its proper divisors (1).

205012121 is an equidigital number, since it uses as much as digits as its factorization.

205012121 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 40, while the sum is 14.

The square root of 205012121 is about 14318.2443407004. The cubic root of 205012121 is about 589.6484748872.

Adding to 205012121 its reverse (121210502), we get a palindrome (326222623).

It can be divided in two parts, 20501 and 2121, that added together give a palindrome (22622).

The spelling of 205012121 in words is "two hundred five million, twelve thousand, one hundred twenty-one".