204123553 has 4 divisors (see below), whose sum is σ = 204204868. Its totient is φ = 204042240.

The previous prime is 204123541. The next prime is 204123583. The reversal of 204123553 is 355321402.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 355321402 = 2 ⋅177660701.

It can be written as a sum of positive squares in 2 ways, for example, as 122257249 + 81866304 = 11057^2 + 9048^2 .

It is a cyclic number.

It is not a de Polignac number, because 204123553 - 2⁹ = 204123041 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (204123503) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 36768 + ... + 41953.

It is an arithmetic number, because the mean of its divisors is an integer number (51051217).

Almost surely, 2^204123553 is an apocalyptic number.

It is an amenable number.

204123553 is a deficient number, since it is larger than the sum of its proper divisors (81315).

204123553 is an equidigital number, since it uses as much as digits as its factorization.

204123553 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81314.

The product of its (nonzero) digits is 3600, while the sum is 25.

The square root of 204123553 is about 14287.1814225200. The cubic root of 204123553 is about 588.7953520689.

Adding to 204123553 its reverse (355321402), we get a palindrome (559444955).

The spelling of 204123553 in words is "two hundred four million, one hundred twenty-three thousand, five hundred fifty-three".