205609972385 has 8 divisors (see below), whose sum is σ = 250776753576. Its totient is φ = 161791453440.

The previous prime is 205609972357. The next prime is 205609972417. The reversal of 205609972385 is 583279906502.

It can be written as a sum of positive squares in 4 ways, for example, as 21304613521 + 184305358864 = 145961^2 + 429308^2 .

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

It is not a de Polignac number, because 205609972385 - 2²⁴ = 205593195169 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 205609972385.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 337065224 + ... + 337065833.

It is an arithmetic number, because the mean of its divisors is an integer number (31347094197).

Almost surely, 2^205609972385 is an apocalyptic number.

It is an amenable number.

205609972385 is a deficient number, since it is larger than the sum of its proper divisors (45166781191).

205609972385 is an equidigital number, since it uses as much as digits as its factorization.

205609972385 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 674131123.

The product of its (nonzero) digits is 8164800, while the sum is 56.

The spelling of 205609972385 in words is "two hundred five billion, six hundred nine million, nine hundred seventy-two thousand, three hundred eighty-five".