204140561 has 2 divisors, whose sum is σ = 204140562. Its totient is φ = 204140560.

The previous prime is 204140557. The next prime is 204140567. The reversal of 204140561 is 165041402.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 203946961 + 193600 = 14281^2 + 440^2 .

It is a cyclic number.

It is not a de Polignac number, because 204140561 - 2² = 204140557 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (204140567) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 102070280 + 102070281.

It is an arithmetic number, because the mean of its divisors is an integer number (102070281).

Almost surely, 2^204140561 is an apocalyptic number.

It is an amenable number.

204140561 is a deficient number, since it is larger than the sum of its proper divisors (1).

204140561 is an equidigital number, since it uses as much as digits as its factorization.

204140561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 960, while the sum is 23.

The square root of 204140561 is about 14287.7766289930. The cubic root of 204140561 is about 588.8117048334.

Adding to 204140561 its reverse (165041402), we get a palindrome (369181963).

The spelling of 204140561 in words is "two hundred four million, one hundred forty thousand, five hundred sixty-one".