205042745255717 has 4 divisors (see below), whose sum is σ = 205110572829120. Its totient is φ = 204974917682316.

The previous prime is 205042745255687. The next prime is 205042745255729. The reversal of 205042745255717 is 717552547240502.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 205042745255717 - 2²⁰ = 205042744207141 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205042745255017) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 33913782167 + ... + 33913788212.

It is an arithmetic number, because the mean of its divisors is an integer number (51277643207280).

Almost surely, 2^{205042745255717} is an apocalyptic number.

It is an amenable number.

205042745255717 is a deficient number, since it is larger than the sum of its proper divisors (67827573403).

205042745255717 is an equidigital number, since it uses as much as digits as its factorization.

205042745255717 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 67827573402.

The product of its (nonzero) digits is 27440000, while the sum is 56.

The spelling of 205042745255717 in words is "two hundred five trillion, forty-two billion, seven hundred forty-five million, two hundred fifty-five thousand, seven hundred seventeen".