25471271981 has 2 divisors, whose sum is σ = 25471271982. Its totient is φ = 25471271980.

The previous prime is 25471271977. The next prime is 25471271999. The reversal of 25471271981 is 18917217452.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15170848900 + 10300423081 = 123170^2 + 101491^2 .

It is a cyclic number.

It is not a de Polignac number, because 25471271981 - 2² = 25471271977 is a prime.

It is a super-2 number, since 2×25471271981² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (25471271971) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12735635990 + 12735635991.

It is an arithmetic number, because the mean of its divisors is an integer number (12735635991).

Almost surely, 2^25471271981 is an apocalyptic number.

It is an amenable number.

25471271981 is a deficient number, since it is larger than the sum of its proper divisors (1).

25471271981 is an equidigital number, since it uses as much as digits as its factorization.

25471271981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 282240, while the sum is 47.

The spelling of 25471271981 in words is "twenty-five billion, four hundred seventy-one million, two hundred seventy-one thousand, nine hundred eighty-one".