25561165403 has 4 divisors (see below), whose sum is σ = 25564734120. Its totient is φ = 25557596688.

The previous prime is 25561165387. The next prime is 25561165411. The reversal of 25561165403 is 30456116552.

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

It is a cyclic number.

It is not a de Polignac number, because 25561165403 - 2⁴ = 25561165387 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (25561165463) 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, 1773593 + ... + 1787946.

It is an arithmetic number, because the mean of its divisors is an integer number (6391183530).

Almost surely, 2^25561165403 is an apocalyptic number.

25561165403 is a deficient number, since it is larger than the sum of its proper divisors (3568717).

25561165403 is an equidigital number, since it uses as much as digits as its factorization.

25561165403 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3568716.

The product of its (nonzero) digits is 108000, while the sum is 38.

The spelling of 25561165403 in words is "twenty-five billion, five hundred sixty-one million, one hundred sixty-five thousand, four hundred three".