205111121 has 4 divisors (see below), whose sum is σ = 205139892. Its totient is φ = 205082352.

The previous prime is 205111117. The next prime is 205111133. The reversal of 205111121 is 121111502.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 74580496 + 130530625 = 8636^2 + 11425^2 .

It is a cyclic number.

It is not a de Polignac number, because 205111121 - 2² = 205111117 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 205111096 and 205111105.

It is not an unprimeable number, because it can be changed into a prime (205111111) 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, 5171 + ... + 20903.

It is an arithmetic number, because the mean of its divisors is an integer number (51284973).

Almost surely, 2^205111121 is an apocalyptic number.

It is an amenable number.

205111121 is a deficient number, since it is larger than the sum of its proper divisors (28771).

205111121 is a wasteful number, since it uses less digits than its factorization.

205111121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28770.

The product of its (nonzero) digits is 20, while the sum is 14.

The square root of 205111121 is about 14321.7010512020. The cubic root of 205111121 is about 589.7433730243.

Adding to 205111121 its reverse (121111502), we get a palindrome (326222623).

The spelling of 205111121 in words is "two hundred five million, one hundred eleven thousand, one hundred twenty-one".