25897821181 has 4 divisors (see below), whose sum is σ = 26597762332. Its totient is φ = 25197880032.

The previous prime is 25897821133. The next prime is 25897821211. The reversal of 25897821181 is 18112879852.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 8749918681 + 17147902500 = 93541^2 + 130950^2 .

It is a cyclic number.

It is not a de Polignac number, because 25897821181 - 2¹³ = 25897812989 is a prime.

It is a super-2 number, since 2×25897821181² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25897821281) 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 in 3 ways as a sum of consecutive naturals, for example, 349970520 + ... + 349970593.

It is an arithmetic number, because the mean of its divisors is an integer number (6649440583).

Almost surely, 2^25897821181 is an apocalyptic number.

It is an amenable number.

25897821181 is a deficient number, since it is larger than the sum of its proper divisors (699941151).

25897821181 is an equidigital number, since it uses as much as digits as its factorization.

25897821181 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 699941150.

The product of its digits is 645120, while the sum is 52.

The spelling of 25897821181 in words is "twenty-five billion, eight hundred ninety-seven million, eight hundred twenty-one thousand, one hundred eighty-one".