25206565681 has 12 divisors (see below), whose sum is σ = 27538615440. Its totient is φ = 22881320280.

The previous prime is 25206565679. The next prime is 25206565751. The reversal of 25206565681 is 18656560252.

It is not a de Polignac number, because 25206565681 - 2¹ = 25206565679 is a prime.

It is a super-2 number, since 2×25206565681² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (25206560681) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 8575110 + ... + 8578048.

It is an arithmetic number, because the mean of its divisors is an integer number (2294884620).

Almost surely, 2^25206565681 is an apocalyptic number.

It is an amenable number.

25206565681 is a deficient number, since it is larger than the sum of its proper divisors (2332049759).

25206565681 is an frugal number, since it uses more digits than its factorization.

25206565681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4716 (or 3833 counting only the distinct ones).

The product of its (nonzero) digits is 864000, while the sum is 46.

The spelling of 25206565681 in words is "twenty-five billion, two hundred six million, five hundred sixty-five thousand, six hundred eighty-one".