25915191861 has 48 divisors (see below), whose sum is σ = 38585279040. Its totient is φ = 15379372800.

The previous prime is 25915191857. The next prime is 25915191889. The reversal of 25915191861 is 16819151952.

It is a happy number.

It is not a de Polignac number, because 25915191861 - 2² = 25915191857 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 25915191861.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25915191821) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 12404505 + ... + 12406593.

It is an arithmetic number, because the mean of its divisors is an integer number (803859980).

Almost surely, 2^25915191861 is an apocalyptic number.

It is an amenable number.

25915191861 is a deficient number, since it is larger than the sum of its proper divisors (12670087179).

25915191861 is a wasteful number, since it uses less digits than its factorization.

25915191861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2498 (or 2467 counting only the distinct ones).

The product of its digits is 194400, while the sum is 48.

The spelling of 25915191861 in words is "twenty-five billion, nine hundred fifteen million, one hundred ninety-one thousand, eight hundred sixty-one".