25539617881 has 2 divisors, whose sum is σ = 25539617882. Its totient is φ = 25539617880.

The previous prime is 25539617879. The next prime is 25539617897. The reversal of 25539617881 is 18871693552.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 23833184400 + 1706433481 = 154380^2 + 41309^2 .

It is a cyclic number.

It is not a de Polignac number, because 25539617881 - 2¹ = 25539617879 is a prime.

It is a super-2 number, since 2×25539617881² (a number of 22 digits) contains 22 as substring.

Together with 25539617879, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (25539617681) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12769808940 + 12769808941.

It is an arithmetic number, because the mean of its divisors is an integer number (12769808941).

Almost surely, 2^25539617881 is an apocalyptic number.

It is an amenable number.

25539617881 is a deficient number, since it is larger than the sum of its proper divisors (1).

25539617881 is an equidigital number, since it uses as much as digits as its factorization.

25539617881 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3628800, while the sum is 55.

The spelling of 25539617881 in words is "twenty-five billion, five hundred thirty-nine million, six hundred seventeen thousand, eight hundred eighty-one".