25664981009 has 2 divisors, whose sum is σ = 25664981010. Its totient is φ = 25664981008.

The previous prime is 25664980963. The next prime is 25664981077. The reversal of 25664981009 is 90018946652.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18048579025 + 7616401984 = 134345^2 + 87272^2 .

It is a cyclic number.

It is not a de Polignac number, because 25664981009 - 2⁸ = 25664980753 is a prime.

It is not a weakly prime, because it can be changed into another prime (25664981099) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12832490504 + 12832490505.

It is an arithmetic number, because the mean of its divisors is an integer number (12832490505).

Almost surely, 2^25664981009 is an apocalyptic number.

It is an amenable number.

25664981009 is a deficient number, since it is larger than the sum of its proper divisors (1).

25664981009 is an equidigital number, since it uses as much as digits as its factorization.

25664981009 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 933120, while the sum is 50.

The spelling of 25664981009 in words is "twenty-five billion, six hundred sixty-four million, nine hundred eighty-one thousand, nine".