25604812817 has 2 divisors, whose sum is σ = 25604812818. Its totient is φ = 25604812816.

The previous prime is 25604812781. The next prime is 25604812879. The reversal of 25604812817 is 71821840652.

Together with previous prime (25604812781) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 23846771776 + 1758041041 = 154424^2 + 41929^2 .

It is a cyclic number.

It is not a de Polignac number, because 25604812817 - 2²² = 25600618513 is a prime.

It is not a weakly prime, because it can be changed into another prime (25604812217) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12802406408 + 12802406409.

It is an arithmetic number, because the mean of its divisors is an integer number (12802406409).

Almost surely, 2^25604812817 is an apocalyptic number.

It is an amenable number.

25604812817 is a deficient number, since it is larger than the sum of its proper divisors (1).

25604812817 is an equidigital number, since it uses as much as digits as its factorization.

25604812817 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 215040, while the sum is 44.

The spelling of 25604812817 in words is "twenty-five billion, six hundred four million, eight hundred twelve thousand, eight hundred seventeen".