26561609 has 2 divisors, whose sum is σ = 26561610. Its totient is φ = 26561608.

The previous prime is 26561603. The next prime is 26561641. The reversal of 26561609 is 90616562.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 26296384 + 265225 = 5128^2 + 515^2 .

It is a cyclic number.

It is not a de Polignac number, because 26561609 - 2¹⁶ = 26496073 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (26561603) 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, 13280804 + 13280805.

It is an arithmetic number, because the mean of its divisors is an integer number (13280805).

Almost surely, 2^26561609 is an apocalyptic number.

It is an amenable number.

26561609 is a deficient number, since it is larger than the sum of its proper divisors (1).

26561609 is an equidigital number, since it uses as much as digits as its factorization.

26561609 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 19440, while the sum is 35.

The square root of 26561609 is about 5153.7955916004. The cubic root of 26561609 is about 298.3674618080.

The spelling of 26561609 in words is "twenty-six million, five hundred sixty-one thousand, six hundred nine".