25805525861 has 2 divisors, whose sum is σ = 25805525862. Its totient is φ = 25805525860.

The previous prime is 25805525813. The next prime is 25805525891. The reversal of 25805525861 is 16852550852.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 24236573761 + 1568952100 = 155681^2 + 39610^2 .

It is a cyclic number.

It is not a de Polignac number, because 25805525861 - 2¹⁰ = 25805524837 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (25805525891) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12902762930 + 12902762931.

It is an arithmetic number, because the mean of its divisors is an integer number (12902762931).

Almost surely, 2^25805525861 is an apocalyptic number.

It is an amenable number.

25805525861 is a deficient number, since it is larger than the sum of its proper divisors (1).

25805525861 is an equidigital number, since it uses as much as digits as its factorization.

25805525861 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 960000, while the sum is 47.

The spelling of 25805525861 in words is "twenty-five billion, eight hundred five million, five hundred twenty-five thousand, eight hundred sixty-one".