204224021 has 4 divisors (see below), whose sum is σ = 204841344. Its totient is φ = 203606700.

The previous prime is 204224011. The next prime is 204224023. The reversal of 204224021 is 120422402.

It is a happy number.

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, and also an emirpimes, since its reverse is a distinct semiprime: 120422402 = 2 ⋅60211201.

It is a cyclic number.

It is not a de Polignac number, because 204224021 - 2¹⁴ = 204207637 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (204224023) 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, 308165 + ... + 308826.

It is an arithmetic number, because the mean of its divisors is an integer number (51210336).

Almost surely, 2^204224021 is an apocalyptic number.

It is an amenable number.

204224021 is a deficient number, since it is larger than the sum of its proper divisors (617323).

204224021 is an equidigital number, since it uses as much as digits as its factorization.

204224021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 617322.

The product of its (nonzero) digits is 256, while the sum is 17.

The square root of 204224021 is about 14290.6970088936. The cubic root of 204224021 is about 588.8919363646.

Adding to 204224021 its reverse (120422402), we get a palindrome (324646423).

The spelling of 204224021 in words is "two hundred four million, two hundred twenty-four thousand, twenty-one".