25561872513 has 36 divisors (see below), whose sum is σ = 38514997248. Its totient is φ = 16963859160.

The previous prime is 25561872499. The next prime is 25561872521. The reversal of 25561872513 is 31527816552.

25561872513 is a `hidden beast` number, since 2 + 5 + 5 + 61 + 8 + 72 + 513 = 666.

It is not a de Polignac number, because 25561872513 - 2⁵ = 25561872481 is a prime.

It is not an unprimeable number, because it can be changed into a prime (25561872533) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 1454368 + ... + 1471838.

Almost surely, 2^25561872513 is an apocalyptic number.

It is an amenable number.

25561872513 is a deficient number, since it is larger than the sum of its proper divisors (12953124735).

25561872513 is an frugal number, since it uses more digits than its factorization.

25561872513 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17718 (or 17697 counting only the distinct ones).

The product of its digits is 504000, while the sum is 45.

The spelling of 25561872513 in words is "twenty-five billion, five hundred sixty-one million, eight hundred seventy-two thousand, five hundred thirteen".