205242101 has 4 divisors (see below), whose sum is σ = 205584204. Its totient is φ = 204900000.

The previous prime is 205242097. The next prime is 205242109. The reversal of 205242101 is 101242502.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 101242502 = 2 ⋅50621251.

It can be written as a sum of positive squares in 2 ways, for example, as 100200100 + 105042001 = 10010^2 + 10249^2 .

It is a cyclic number.

It is not a de Polignac number, because 205242101 - 2² = 205242097 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 205242101.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205242109) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 170150 + ... + 171351.

It is an arithmetic number, because the mean of its divisors is an integer number (51396051).

Almost surely, 2^205242101 is an apocalyptic number.

It is an amenable number.

205242101 is a deficient number, since it is larger than the sum of its proper divisors (342103).

205242101 is an equidigital number, since it uses as much as digits as its factorization.

205242101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 342102.

The product of its (nonzero) digits is 160, while the sum is 17.

The square root of 205242101 is about 14326.2731022412. The cubic root of 205242101 is about 589.8688792217.

Adding to 205242101 its reverse (101242502), we get a palindrome (306484603).

The spelling of 205242101 in words is "two hundred five million, two hundred forty-two thousand, one hundred one".