204243657689 has 4 divisors (see below), whose sum is σ = 204283608756. Its totient is φ = 204203706624.

The previous prime is 204243657677. The next prime is 204243657701. The reversal of 204243657689 is 986756342402.

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

It is an interprime number because it is at equal distance from previous prime (204243657677) and next prime (204243657701).

It can be written as a sum of positive squares in 2 ways, for example, as 23845536400 + 180398121289 = 154420^2 + 424733^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-204243657689 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (204243657619) 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, 19967864 + ... + 19978089.

It is an arithmetic number, because the mean of its divisors is an integer number (51070902189).

Almost surely, 2^204243657689 is an apocalyptic number.

It is an amenable number.

204243657689 is a deficient number, since it is larger than the sum of its proper divisors (39951067).

204243657689 is an equidigital number, since it uses as much as digits as its factorization.

204243657689 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39951066.

The product of its (nonzero) digits is 17418240, while the sum is 56.

The spelling of 204243657689 in words is "two hundred four billion, two hundred forty-three million, six hundred fifty-seven thousand, six hundred eighty-nine".