25609469981 has 2 divisors, whose sum is σ = 25609469982. Its totient is φ = 25609469980.

The previous prime is 25609469971. The next prime is 25609470049. The reversal of 25609469981 is 18996490652.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15636252025 + 9973217956 = 125045^2 + 99866^2 .

It is a cyclic number.

It is not a de Polignac number, because 25609469981 - 2³⁰ = 24535728157 is a prime.

It is a super-2 number, since 2×25609469981² (a number of 22 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 25609469981.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (25609469971) 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, 12804734990 + 12804734991.

It is an arithmetic number, because the mean of its divisors is an integer number (12804734991).

Almost surely, 2^25609469981 is an apocalyptic number.

It is an amenable number.

25609469981 is a deficient number, since it is larger than the sum of its proper divisors (1).

25609469981 is an equidigital number, since it uses as much as digits as its factorization.

25609469981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8398080, while the sum is 59.

The spelling of 25609469981 in words is "twenty-five billion, six hundred nine million, four hundred sixty-nine thousand, nine hundred eighty-one".