204405221 has 4 divisors (see below), whose sum is σ = 204606444. Its totient is φ = 204204000.

The previous prime is 204405217. The next prime is 204405239. The reversal of 204405221 is 122504402.

It is a happy number.

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 54612100 + 149793121 = 7390^2 + 12239^2 .

It is a cyclic number.

It is not a de Polignac number, because 204405221 - 2² = 204405217 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 204405193 and 204405202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (204405241) 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, 99080 + ... + 101121.

It is an arithmetic number, because the mean of its divisors is an integer number (51151611).

Almost surely, 2^204405221 is an apocalyptic number.

It is an amenable number.

204405221 is a deficient number, since it is larger than the sum of its proper divisors (201223).

204405221 is a wasteful number, since it uses less digits than its factorization.

204405221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 201222.

The product of its (nonzero) digits is 640, while the sum is 20.

The square root of 204405221 is about 14297.0353919965. The cubic root of 204405221 is about 589.0660518202.

Adding to 204405221 its reverse (122504402), we get a palindrome (326909623).

The spelling of 204405221 in words is "two hundred four million, four hundred five thousand, two hundred twenty-one".