25565256553 has 4 divisors (see below), whose sum is σ = 25728092740. Its totient is φ = 25402420368.

The previous prime is 25565256529. The next prime is 25565256589. The reversal of 25565256553 is 35565256552.

It is a happy number.

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 18799700544 + 6765556009 = 137112^2 + 82253^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-25565256553 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 25565256497 and 25565256506.

It is not an unprimeable number, because it can be changed into a prime (25565254553) 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 in 3 ways as a sum of consecutive naturals, for example, 81417858 + ... + 81418171.

It is an arithmetic number, because the mean of its divisors is an integer number (6432023185).

Almost surely, 2^25565256553 is an apocalyptic number.

It is an amenable number.

25565256553 is a deficient number, since it is larger than the sum of its proper divisors (162836187).

25565256553 is a wasteful number, since it uses less digits than its factorization.

25565256553 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 162836186.

The product of its digits is 6750000, while the sum is 49.

Subtracting 25565256553 from its reverse (35565256552), we obtain a palindrome (9999999999).

The spelling of 25565256553 in words is "twenty-five billion, five hundred sixty-five million, two hundred fifty-six thousand, five hundred fifty-three".