205660591 has 4 divisors (see below), whose sum is σ = 205928800. Its totient is φ = 205392384.

The previous prime is 205660583. The next prime is 205660597. The reversal of 205660591 is 195066502.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 205660591 - 2³ = 205660583 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 (205660597) 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, 132951 + ... + 134488.

It is an arithmetic number, because the mean of its divisors is an integer number (51482200).

Almost surely, 2^205660591 is an apocalyptic number.

205660591 is a deficient number, since it is larger than the sum of its proper divisors (268209).

205660591 is an equidigital number, since it uses as much as digits as its factorization.

205660591 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 268208.

The product of its (nonzero) digits is 16200, while the sum is 34.

The square root of 205660591 is about 14340.8713473066. The cubic root of 205660591 is about 590.2695225542.

The spelling of 205660591 in words is "two hundred five million, six hundred sixty thousand, five hundred ninety-one".