25491353881 has 4 divisors (see below), whose sum is σ = 29132975872. Its totient is φ = 21849731892.

The previous prime is 25491353879. The next prime is 25491353893. The reversal of 25491353881 is 18835319452.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 25491353881 - 2¹ = 25491353879 is a prime.

It is a super-2 number, since 2×25491353881² (a number of 22 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (25491353801) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1820810985 + ... + 1820810998.

It is an arithmetic number, because the mean of its divisors is an integer number (7283243968).

Almost surely, 2^25491353881 is an apocalyptic number.

It is an amenable number.

25491353881 is a deficient number, since it is larger than the sum of its proper divisors (3641621991).

25491353881 is an equidigital number, since it uses as much as digits as its factorization.

25491353881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3641621990.

The product of its digits is 1036800, while the sum is 49.

The spelling of 25491353881 in words is "twenty-five billion, four hundred ninety-one million, three hundred fifty-three thousand, eight hundred eighty-one".