205560661 has 4 divisors (see below), whose sum is σ = 209044800. Its totient is φ = 202076524.

The previous prime is 205560653. The next prime is 205560701. The reversal of 205560661 is 166065502.

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 205560661 - 2³ = 205560653 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 (205560611) 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, 1741981 + ... + 1742098.

It is an arithmetic number, because the mean of its divisors is an integer number (52261200).

Almost surely, 2^205560661 is an apocalyptic number.

It is an amenable number.

205560661 is a deficient number, since it is larger than the sum of its proper divisors (3484139).

205560661 is an equidigital number, since it uses as much as digits as its factorization.

205560661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3484138.

The product of its (nonzero) digits is 10800, while the sum is 31.

The square root of 205560661 is about 14337.3868260573. The cubic root of 205560661 is about 590.1739035388.

The spelling of 205560661 in words is "two hundred five million, five hundred sixty thousand, six hundred sixty-one".