25781161669 has 2 divisors, whose sum is σ = 25781161670. Its totient is φ = 25781161668.

The previous prime is 25781161667. The next prime is 25781161711. The reversal of 25781161669 is 96616118752.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13601390625 + 12179771044 = 116625^2 + 110362^2 .

It is a cyclic number.

It is not a de Polignac number, because 25781161669 - 2¹ = 25781161667 is a prime.

It is a super-2 number, since 2×25781161669² (a number of 22 digits) contains 22 as substring.

Together with 25781161667, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (25781161667) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12890580834 + 12890580835.

It is an arithmetic number, because the mean of its divisors is an integer number (12890580835).

Almost surely, 2^25781161669 is an apocalyptic number.

It is an amenable number.

25781161669 is a deficient number, since it is larger than the sum of its proper divisors (1).

25781161669 is an equidigital number, since it uses as much as digits as its factorization.

25781161669 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1088640, while the sum is 52.

The spelling of 25781161669 in words is "twenty-five billion, seven hundred eighty-one million, one hundred sixty-one thousand, six hundred sixty-nine".