25561612829 has 4 divisors (see below), whose sum is σ = 25562610300. Its totient is φ = 25560615360.

The previous prime is 25561612807. The next prime is 25561612849. The reversal of 25561612829 is 92821616552.

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 10424001604 + 15137611225 = 102098^2 + 123035^2 .

It is a cyclic number.

It is not a de Polignac number, because 25561612829 - 2¹² = 25561608733 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25561612849) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 459254 + ... + 511895.

It is an arithmetic number, because the mean of its divisors is an integer number (6390652575).

Almost surely, 2^25561612829 is an apocalyptic number.

It is an amenable number.

25561612829 is a deficient number, since it is larger than the sum of its proper divisors (997471).

25561612829 is an equidigital number, since it uses as much as digits as its factorization.

25561612829 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 997470.

The product of its digits is 518400, while the sum is 47.

The spelling of 25561612829 in words is "twenty-five billion, five hundred sixty-one million, six hundred twelve thousand, eight hundred twenty-nine".