25638818609 has 2 divisors, whose sum is σ = 25638818610. Its totient is φ = 25638818608.

The previous prime is 25638818581. The next prime is 25638818693. The reversal of 25638818609 is 90681883652.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 23635987600 + 2002831009 = 153740^2 + 44753^2 .

It is a cyclic number.

It is not a de Polignac number, because 25638818609 - 2²⁰ = 25637770033 is a prime.

It is not a weakly prime, because it can be changed into another prime (25638818509) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12819409304 + 12819409305.

It is an arithmetic number, because the mean of its divisors is an integer number (12819409305).

Almost surely, 2^25638818609 is an apocalyptic number.

It is an amenable number.

25638818609 is a deficient number, since it is larger than the sum of its proper divisors (1).

25638818609 is an equidigital number, since it uses as much as digits as its factorization.

25638818609 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4976640, while the sum is 56.

The spelling of 25638818609 in words is "twenty-five billion, six hundred thirty-eight million, eight hundred eighteen thousand, six hundred nine".