205106561 has 8 divisors (see below), whose sum is σ = 225094464. Its totient is φ = 185342320.

The previous prime is 205106549. The next prime is 205106563. The reversal of 205106561 is 165601502.

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 205106561 - 2²⁶ = 137997697 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 205106561.

It is not an unprimeable number, because it can be changed into a prime (205106563) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 53990 + ... + 57663.

It is an arithmetic number, because the mean of its divisors is an integer number (28136808).

Almost surely, 2^205106561 is an apocalyptic number.

It is an amenable number.

205106561 is a deficient number, since it is larger than the sum of its proper divisors (19987903).

205106561 is a wasteful number, since it uses less digits than its factorization.

205106561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 111831.

The product of its (nonzero) digits is 1800, while the sum is 26.

The square root of 205106561 is about 14321.5418513511. The cubic root of 205106561 is about 589.7390026295.

The spelling of 205106561 in words is "two hundred five million, one hundred six thousand, five hundred sixty-one".