25918517891 has 16 divisors (see below), whose sum is σ = 29696045568. Its totient is φ = 22159785600.

The previous prime is 25918517887. The next prime is 25918517939. The reversal of 25918517891 is 19871581952.

It is a cyclic number.

It is not a de Polignac number, because 25918517891 - 2² = 25918517887 is a prime.

It is a super-3 number, since 3×25918517891³ (a number of 32 digits) contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (25918517791) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6123746 + ... + 6127976.

It is an arithmetic number, because the mean of its divisors is an integer number (1856002848).

Almost surely, 2^25918517891 is an apocalyptic number.

25918517891 is a deficient number, since it is larger than the sum of its proper divisors (3777527677).

25918517891 is a wasteful number, since it uses less digits than its factorization.

25918517891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6242.

The product of its digits is 1814400, while the sum is 56.

The spelling of 25918517891 in words is "twenty-five billion, nine hundred eighteen million, five hundred seventeen thousand, eight hundred ninety-one".