25781187191 has 24 divisors (see below), whose sum is σ = 29588978160. Its totient is φ = 22366077696.

The previous prime is 25781187151. The next prime is 25781187217. The reversal of 25781187191 is 19178118752.

It is a de Polignac number, because none of the positive numbers 2^k-25781187191 is a prime.

It is a super-2 number, since 2×25781187191² (a number of 22 digits) contains 22 as substring.

It is a hoax number, since the sum of its digits (50) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25781187121) 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 in 23 ways as a sum of consecutive naturals, for example, 170300 + ... + 283838.

It is an arithmetic number, because the mean of its divisors is an integer number (1232874090).

Almost surely, 2^25781187191 is an apocalyptic number.

25781187191 is a deficient number, since it is larger than the sum of its proper divisors (3807790969).

25781187191 is a wasteful number, since it uses less digits than its factorization.

25781187191 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 113631 (or 113612 counting only the distinct ones).

The product of its digits is 282240, while the sum is 50.

The spelling of 25781187191 in words is "twenty-five billion, seven hundred eighty-one million, one hundred eighty-seven thousand, one hundred ninety-one".