25662809561 has 12 divisors (see below), whose sum is σ = 27319704048. Its totient is φ = 24101385792.

The previous prime is 25662809533. The next prime is 25662809569. The reversal of 25662809561 is 16590826652.

It is not a de Polignac number, because 25662809561 - 2¹⁰ = 25662808537 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (25662809569) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 39890 + ... + 230036.

It is an arithmetic number, because the mean of its divisors is an integer number (2276642004).

Almost surely, 2^25662809561 is an apocalyptic number.

It is an amenable number.

25662809561 is a deficient number, since it is larger than the sum of its proper divisors (1656894487).

25662809561 is a wasteful number, since it uses less digits than its factorization.

25662809561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 190648 (or 190631 counting only the distinct ones).

The product of its (nonzero) digits is 1555200, while the sum is 50.

The spelling of 25662809561 in words is "twenty-five billion, six hundred sixty-two million, eight hundred nine thousand, five hundred sixty-one".