205409389643 has 2 divisors, whose sum is σ = 205409389644. Its totient is φ = 205409389642.

The previous prime is 205409389613. The next prime is 205409389727. The reversal of 205409389643 is 346983904502.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 205409389643 - 2²² = 205405195339 is a prime.

It is not a weakly prime, because it can be changed into another prime (205409389613) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 102704694821 + 102704694822.

It is an arithmetic number, because the mean of its divisors is an integer number (102704694822).

Almost surely, 2^205409389643 is an apocalyptic number.

205409389643 is a deficient number, since it is larger than the sum of its proper divisors (1).

205409389643 is an equidigital number, since it uses as much as digits as its factorization.

205409389643 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5598720, while the sum is 53.

The spelling of 205409389643 in words is "two hundred five billion, four hundred nine million, three hundred eighty-nine thousand, six hundred forty-three".