205253021 has 4 divisors (see below), whose sum is σ = 205520700. Its totient is φ = 204985344.

The previous prime is 205252987. The next prime is 205253051. The reversal of 205253021 is 120352502.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 99780121 + 105472900 = 9989^2 + 10270^2 .

It is a cyclic number.

It is not a de Polignac number, because 205253021 - 2¹⁰ = 205251997 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 205252984 and 205253002.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205253051) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 132686 + ... + 134223.

It is an arithmetic number, because the mean of its divisors is an integer number (51380175).

Almost surely, 2^205253021 is an apocalyptic number.

It is an amenable number.

205253021 is a deficient number, since it is larger than the sum of its proper divisors (267679).

205253021 is an equidigital number, since it uses as much as digits as its factorization.

205253021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 267678.

The product of its (nonzero) digits is 600, while the sum is 20.

The square root of 205253021 is about 14326.6542151334. The cubic root of 205253021 is about 589.8793404508.

The spelling of 205253021 in words is "two hundred five million, two hundred fifty-three thousand, twenty-one".