205111311243 has 4 divisors (see below), whose sum is σ = 273481748328. Its totient is φ = 136740874160.

The previous prime is 205111311221. The next prime is 205111311247. The reversal of 205111311243 is 342113111502.

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 205111311243 - 2²² = 205107116939 is a prime.

It is not an unprimeable number, because it can be changed into a prime (205111311247) 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, 34185218538 + ... + 34185218543.

It is an arithmetic number, because the mean of its divisors is an integer number (68370437082).

Almost surely, 2^205111311243 is an apocalyptic number.

205111311243 is a deficient number, since it is larger than the sum of its proper divisors (68370437085).

205111311243 is an equidigital number, since it uses as much as digits as its factorization.

205111311243 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 68370437084.

The product of its (nonzero) digits is 720, while the sum is 24.

Adding to 205111311243 its reverse (342113111502), we get a palindrome (547224422745).

The spelling of 205111311243 in words is "two hundred five billion, one hundred eleven million, three hundred eleven thousand, two hundred forty-three".