205121023 has 2 divisors, whose sum is σ = 205121024. Its totient is φ = 205121022.

The previous prime is 205121009. The next prime is 205121039. The reversal of 205121023 is 320121502.

It is an a-pointer prime, because the next prime (205121039) can be obtained adding 205121023 to its sum of digits (16).

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 205121023 - 2²¹ = 203023871 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 205120988 and 205121006.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (205121003) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 102560511 + 102560512.

It is an arithmetic number, because the mean of its divisors is an integer number (102560512).

Almost surely, 2^205121023 is an apocalyptic number.

205121023 is a deficient number, since it is larger than the sum of its proper divisors (1).

205121023 is an equidigital number, since it uses as much as digits as its factorization.

205121023 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 205121023 is about 14322.0467461882. The cubic root of 205121023 is about 589.7528630752.

Adding to 205121023 its reverse (320121502), we get a palindrome (525242525).

The spelling of 205121023 in words is "two hundred five million, one hundred twenty-one thousand, twenty-three".