280000561 has 2 divisors, whose sum is σ = 280000562. Its totient is φ = 280000560.

The previous prime is 280000543. The next prime is 280000577. The reversal of 280000561 is 165000082.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 214066161 + 65934400 = 14631^2 + 8120^2 .

It is a cyclic number.

It is not a de Polignac number, because 280000561 - 2¹¹ = 279998513 is a prime.

It is not a weakly prime, because it can be changed into another prime (280000531) 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, 140000280 + 140000281.

It is an arithmetic number, because the mean of its divisors is an integer number (140000281).

Almost surely, 2^280000561 is an apocalyptic number.

It is an amenable number.

280000561 is a deficient number, since it is larger than the sum of its proper divisors (1).

280000561 is an equidigital number, since it uses as much as digits as its factorization.

280000561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 480, while the sum is 22.

The square root of 280000561 is about 16733.2172937544. The cubic root of 280000561 is about 654.2136989584.

The spelling of 280000561 in words is "two hundred eighty million, five hundred sixty-one", and thus it is an aban number.