205242439 has 2 divisors, whose sum is σ = 205242440. Its totient is φ = 205242438.

The previous prime is 205242437. The next prime is 205242481. The reversal of 205242439 is 934242502.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 205242439 - 2¹ = 205242437 is a prime.

Together with 205242437, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 205242439.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (205242437) 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, 102621219 + 102621220.

It is an arithmetic number, because the mean of its divisors is an integer number (102621220).

Almost surely, 2^205242439 is an apocalyptic number.

205242439 is a deficient number, since it is larger than the sum of its proper divisors (1).

205242439 is an equidigital number, since it uses as much as digits as its factorization.

205242439 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 17280, while the sum is 31.

The square root of 205242439 is about 14326.2848987447. The cubic root of 205242439 is about 589.8692030272.

The spelling of 205242439 in words is "two hundred five million, two hundred forty-two thousand, four hundred thirty-nine".