205631985 has 16 divisors (see below), whose sum is σ = 354320064. Its totient is φ = 101234112.

The previous prime is 205631963. The next prime is 205631989. The reversal of 205631985 is 589136502.

It is not a de Polignac number, because 205631985 - 2¹⁰ = 205630961 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is not an unprimeable number, because it can be changed into a prime (205631989) 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 15 ways as a sum of consecutive naturals, for example, 527067 + ... + 527456.

It is an arithmetic number, because the mean of its divisors is an integer number (22145004).

Almost surely, 2^205631985 is an apocalyptic number.

It is an amenable number.

205631985 is a deficient number, since it is larger than the sum of its proper divisors (148688079).

205631985 is a wasteful number, since it uses less digits than its factorization.

205631985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1054544.

The product of its (nonzero) digits is 64800, while the sum is 39.

The square root of 205631985 is about 14339.8739534209. The cubic root of 205631985 is about 590.2421537831.

The spelling of 205631985 in words is "two hundred five million, six hundred thirty-one thousand, nine hundred eighty-five".