205612661 has 4 divisors (see below), whose sum is σ = 216434400. Its totient is φ = 194790924.

The previous prime is 205612657. The next prime is 205612679. The reversal of 205612661 is 166216502.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 205612661 - 2² = 205612657 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 (205612621) 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 3 ways as a sum of consecutive naturals, for example, 5410841 + ... + 5410878.

It is an arithmetic number, because the mean of its divisors is an integer number (54108600).

Almost surely, 2^205612661 is an apocalyptic number.

It is an amenable number.

205612661 is a deficient number, since it is larger than the sum of its proper divisors (10821739).

205612661 is a wasteful number, since it uses less digits than its factorization.

205612661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10821738.

The product of its (nonzero) digits is 4320, while the sum is 29.

The square root of 205612661 is about 14339.2001520308. The cubic root of 205612661 is about 590.2236641228.

The spelling of 205612661 in words is "two hundred five million, six hundred twelve thousand, six hundred sixty-one".