204021161 has 4 divisors (see below), whose sum is σ = 205826772. Its totient is φ = 202215552.

The previous prime is 204021151. The next prime is 204021163. The reversal of 204021161 is 161120402.

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 64899136 + 139122025 = 8056^2 + 11795^2 .

It is a cyclic number.

It is not a de Polignac number, because 204021161 - 2²⁶ = 136912297 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (204021163) 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, 902636 + ... + 902861.

It is an arithmetic number, because the mean of its divisors is an integer number (51456693).

Almost surely, 2^204021161 is an apocalyptic number.

It is an amenable number.

204021161 is a deficient number, since it is larger than the sum of its proper divisors (1805611).

204021161 is a wasteful number, since it uses less digits than its factorization.

204021161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1805610.

The product of its (nonzero) digits is 96, while the sum is 17.

The square root of 204021161 is about 14283.5976210477. The cubic root of 204021161 is about 588.6968855337.

Adding to 204021161 its reverse (161120402), we get a palindrome (365141563).

The spelling of 204021161 in words is "two hundred four million, twenty-one thousand, one hundred sixty-one".