25861778191 has 2 divisors, whose sum is σ = 25861778192. Its totient is φ = 25861778190.

The previous prime is 25861778183. The next prime is 25861778219. The reversal of 25861778191 is 19187716852.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 25861778191 - 2³ = 25861778183 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (25861778101) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12930889095 + 12930889096.

It is an arithmetic number, because the mean of its divisors is an integer number (12930889096).

Almost surely, 2^25861778191 is an apocalyptic number.

25861778191 is a deficient number, since it is larger than the sum of its proper divisors (1).

25861778191 is an equidigital number, since it uses as much as digits as its factorization.

25861778191 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1693440, while the sum is 55.

The spelling of 25861778191 in words is "twenty-five billion, eight hundred sixty-one million, seven hundred seventy-eight thousand, one hundred ninety-one".