25396940581 has 2 divisors, whose sum is σ = 25396940582. Its totient is φ = 25396940580.

The previous prime is 25396940573. The next prime is 25396940593. The reversal of 25396940581 is 18504969352.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 22198020100 + 3198920481 = 148990^2 + 56559^2 .

It is a cyclic number.

It is not a de Polignac number, because 25396940581 - 2³ = 25396940573 is a prime.

It is a super-2 number, since 2×25396940581² (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 (25396949581) 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 as a sum of consecutive naturals, namely, 12698470290 + 12698470291.

It is an arithmetic number, because the mean of its divisors is an integer number (12698470291).

Almost surely, 2^25396940581 is an apocalyptic number.

It is an amenable number.

25396940581 is a deficient number, since it is larger than the sum of its proper divisors (1).

25396940581 is an equidigital number, since it uses as much as digits as its factorization.

25396940581 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2332800, while the sum is 52.

The spelling of 25396940581 in words is "twenty-five billion, three hundred ninety-six million, nine hundred forty thousand, five hundred eighty-one".