25540510531981 has 2 divisors, whose sum is σ = 25540510531982. Its totient is φ = 25540510531980.

The previous prime is 25540510531931. The next prime is 25540510532039. The reversal of 25540510531981 is 18913501504552.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13111423740900 + 12429086791081 = 3620970^2 + 3525491^2 .

It is a cyclic number.

It is not a de Polignac number, because 25540510531981 - 2³³ = 25531920597389 is a prime.

It is a super-2 number, since 2×25540510531981² (a number of 28 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (25540510531931) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12770255265990 + 12770255265991.

It is an arithmetic number, because the mean of its divisors is an integer number (12770255265991).

Almost surely, 2^{25540510531981} is an apocalyptic number.

It is an amenable number.

25540510531981 is a deficient number, since it is larger than the sum of its proper divisors (1).

25540510531981 is an equidigital number, since it uses as much as digits as its factorization.

25540510531981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1080000, while the sum is 49.

The spelling of 25540510531981 in words is "twenty-five trillion, five hundred forty billion, five hundred ten million, five hundred thirty-one thousand, nine hundred eighty-one".