204421645 has 4 divisors (see below), whose sum is σ = 245305980. Its totient is φ = 163537312.

The previous prime is 204421643. The next prime is 204421661. The reversal of 204421645 is 546124402.

204421645 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 34327881 + 170093764 = 5859^2 + 13042^2 .

It is a cyclic number.

It is not a de Polignac number, because 204421645 - 2¹ = 204421643 is a prime.

It is a super-3 number, since 3×204421645³ (a number of 26 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (204421643) 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, 20442160 + ... + 20442169.

It is an arithmetic number, because the mean of its divisors is an integer number (61326495).

Almost surely, 2^204421645 is an apocalyptic number.

It is an amenable number.

204421645 is a deficient number, since it is larger than the sum of its proper divisors (40884335).

204421645 is an equidigital number, since it uses as much as digits as its factorization.

204421645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40884334.

The product of its (nonzero) digits is 7680, while the sum is 28.

The square root of 204421645 is about 14297.6097652720. The cubic root of 204421645 is about 589.0818285890.

The spelling of 204421645 in words is "two hundred four million, four hundred twenty-one thousand, six hundred forty-five".