206255855717 has 4 divisors (see below), whose sum is σ = 207022606380. Its totient is φ = 205489105056.

The previous prime is 206255855671. The next prime is 206255855779. The reversal of 206255855717 is 717558552602.

It is a Cunningham number, because it is equal to 454154²+1.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 13570852036 + 192685003681 = 116494^2 + 438959^2 .

It is a cyclic number.

It is not a de Polignac number, because 206255855717 - 2¹² = 206255851621 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 (206255855417) 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, 383374928 + ... + 383375465.

It is an arithmetic number, because the mean of its divisors is an integer number (51755651595).

Almost surely, 2^206255855717 is an apocalyptic number.

It is an amenable number.

206255855717 is a deficient number, since it is larger than the sum of its proper divisors (766750663).

206255855717 is an equidigital number, since it uses as much as digits as its factorization.

206255855717 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 766750662.

The product of its (nonzero) digits is 5880000, while the sum is 53.

The spelling of 206255855717 in words is "two hundred six billion, two hundred fifty-five million, eight hundred fifty-five thousand, seven hundred seventeen".