205121 has 4 divisors (see below), whose sum is σ = 234432. Its totient is φ = 175812.

The previous prime is 205111. The next prime is 205129. The reversal of 205121 is 121502.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a de Polignac number, because none of the positive numbers 2^k-205121 is a prime.

It is a pancake number, because a pancake can be divided into 205121 parts by 640 straight cuts.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (205129) 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, 14645 + ... + 14658.

It is an arithmetic number, because the mean of its divisors is an integer number (58608).

2²⁰⁵¹²¹ is an apocalyptic number.

It is an amenable number.

205121 is a deficient number, since it is larger than the sum of its proper divisors (29311).

205121 is an equidigital number, since it uses as much as digits as its factorization.

205121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29310.

The product of its (nonzero) digits is 20, while the sum is 11.

The square root of 205121 is about 452.9028593418. The cubic root of 205121 is about 58.9752841032.

Adding to 205121 its reverse (121502), we get a palindrome (326623).

It can be divided in two parts, 2051 and 21, that multiplied together give a triangular number (43071 = T₂₉₃).

The spelling of 205121 in words is "two hundred five thousand, one hundred twenty-one".