205685990797 has 32 divisors (see below), whose sum is σ = 248746803200. Its totient is φ = 166144722048.

The previous prime is 205685990773. The next prime is 205685990831. The reversal of 205685990797 is 797099586502.

It is a cyclic number.

It is not a de Polignac number, because 205685990797 - 2⁷ = 205685990669 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205685990717) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 19958548 + ... + 19968850.

It is an arithmetic number, because the mean of its divisors is an integer number (7773337600).

Almost surely, 2^205685990797 is an apocalyptic number.

It is an amenable number.

205685990797 is a deficient number, since it is larger than the sum of its proper divisors (43060812403).

205685990797 is a wasteful number, since it uses less digits than its factorization.

205685990797 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11105.

The product of its (nonzero) digits is 85730400, while the sum is 67.

The spelling of 205685990797 in words is "two hundred five billion, six hundred eighty-five million, nine hundred ninety thousand, seven hundred ninety-seven".