25681390997 has 2 divisors, whose sum is σ = 25681390998. Its totient is φ = 25681390996.

The previous prime is 25681390961. The next prime is 25681391009. The reversal of 25681390997 is 79909318652.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 25408678801 + 272712196 = 159401^2 + 16514^2 .

It is a cyclic number.

It is not a de Polignac number, because 25681390997 - 2¹⁴ = 25681374613 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (25681390927) 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, 12840695498 + 12840695499.

It is an arithmetic number, because the mean of its divisors is an integer number (12840695499).

Almost surely, 2^25681390997 is an apocalyptic number.

It is an amenable number.

25681390997 is a deficient number, since it is larger than the sum of its proper divisors (1).

25681390997 is an equidigital number, since it uses as much as digits as its factorization.

25681390997 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7348320, while the sum is 59.

The spelling of 25681390997 in words is "twenty-five billion, six hundred eighty-one million, three hundred ninety thousand, nine hundred ninety-seven".