25781161697 has 4 divisors (see below), whose sum is σ = 25945373076. Its totient is φ = 25616950320.

The previous prime is 25781161669. The next prime is 25781161711. The reversal of 25781161697 is 79616118752.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 14142204241 + 11638957456 = 118921^2 + 107884^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-25781161697 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (25781161667) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 82105454 + ... + 82105767.

It is an arithmetic number, because the mean of its divisors is an integer number (6486343269).

Almost surely, 2^25781161697 is an apocalyptic number.

It is an amenable number.

25781161697 is a deficient number, since it is larger than the sum of its proper divisors (164211379).

25781161697 is a wasteful number, since it uses less digits than its factorization.

25781161697 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 164211378.

The product of its digits is 1270080, while the sum is 53.

The spelling of 25781161697 in words is "twenty-five billion, seven hundred eighty-one million, one hundred sixty-one thousand, six hundred ninety-seven".