25861581005861 has 8 divisors (see below), whose sum is σ = 27757958018904. Its totient is φ = 24006882608640.

The previous prime is 25861581005831. The next prime is 25861581005893. The reversal of 25861581005861 is 16850018516852.

It can be written as a sum of positive squares in 4 ways, for example, as 5743835356900 + 20117745648961 = 2396630^2 + 4485281^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 25861581005861 - 2¹⁰ = 25861581004837 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 25861581005797 and 25861581005806.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25861581005831) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10419652670 + ... + 10419655151.

It is an arithmetic number, because the mean of its divisors is an integer number (3469744752363).

Almost surely, 2^{25861581005861} is an apocalyptic number.

It is an amenable number.

25861581005861 is a deficient number, since it is larger than the sum of its proper divisors (1896377013043).

25861581005861 is a wasteful number, since it uses less digits than its factorization.

25861581005861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20839307911.

The product of its (nonzero) digits is 4608000, while the sum is 56.

The spelling of 25861581005861 in words is "twenty-five trillion, eight hundred sixty-one billion, five hundred eighty-one million, five thousand, eight hundred sixty-one".