205664 has 12 divisors (see below), whose sum is σ = 404964. Its totient is φ = 102816.

The previous prime is 205663. The next prime is 205703. The reversal of 205664 is 466502.

205664 = T₉₇ + T₉₈ + ... + T₁₂₈.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 205664.

It is not an unprimeable number, because it can be changed into a prime (205661) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3182 + ... + 3245.

It is an arithmetic number, because the mean of its divisors is an integer number (33747).

2²⁰⁵⁶⁶⁴ is an apocalyptic number.

It is an amenable number.

205664 is a deficient number, since it is larger than the sum of its proper divisors (199300).

205664 is an equidigital number, since it uses as much as digits as its factorization.

205664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6437 (or 6429 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 23.

The square root of 205664 is about 453.5019294336. The cubic root of 205664 is about 59.0272783943.

The spelling of 205664 in words is "two hundred five thousand, six hundred sixty-four".