205043561 has 8 divisors (see below), whose sum is σ = 206182440. Its totient is φ = 203908608.

The previous prime is 205043557. The next prime is 205043569. The reversal of 205043561 is 165340502.

It can be written as a sum of positive squares in 4 ways, for example, as 91087936 + 113955625 = 9544^2 + 10675^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 205043561 - 2² = 205043557 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 205043561.

It is not an unprimeable number, because it can be changed into a prime (205043569) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 186365 + ... + 187461.

It is an arithmetic number, because the mean of its divisors is an integer number (25772805).

Almost surely, 2^205043561 is an apocalyptic number.

It is an amenable number.

205043561 is a deficient number, since it is larger than the sum of its proper divisors (1138879).

205043561 is a wasteful number, since it uses less digits than its factorization.

205043561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1963.

The product of its (nonzero) digits is 3600, while the sum is 26.

The square root of 205043561 is about 14319.3421985788. The cubic root of 205043561 is about 589.6786155449.

The spelling of 205043561 in words is "two hundred five million, forty-three thousand, five hundred sixty-one".