205971009 has 8 divisors (see below), whose sum is σ = 277714080. Its totient is φ = 135770976.

The previous prime is 205970993. The next prime is 205971023. The reversal of 205971009 is 900179502.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 205971009 - 2⁴ = 205970993 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (205971809) 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 7 ways as a sum of consecutive naturals, for example, 385447 + ... + 385980.

It is an arithmetic number, because the mean of its divisors is an integer number (34714260).

Almost surely, 2^205971009 is an apocalyptic number.

It is an amenable number.

205971009 is a deficient number, since it is larger than the sum of its proper divisors (71743071).

205971009 is an equidigital number, since it uses as much as digits as its factorization.

205971009 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 771519.

The product of its (nonzero) digits is 5670, while the sum is 33.

The square root of 205971009 is about 14351.6901095307. The cubic root of 205971009 is about 590.5663517029.

The spelling of 205971009 in words is "two hundred five million, nine hundred seventy-one thousand, nine".