25505287791 has 4 divisors (see below), whose sum is σ = 34007050392. Its totient is φ = 17003525192.

The previous prime is 25505287777. The next prime is 25505287861. The reversal of 25505287791 is 19778250552.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-25505287791 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25505287711) 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, 4250881296 + ... + 4250881301.

It is an arithmetic number, because the mean of its divisors is an integer number (8501762598).

Almost surely, 2^25505287791 is an apocalyptic number.

25505287791 is a deficient number, since it is larger than the sum of its proper divisors (8501762601).

25505287791 is an equidigital number, since it uses as much as digits as its factorization.

25505287791 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8501762600.

The product of its (nonzero) digits is 1764000, while the sum is 51.

The spelling of 25505287791 in words is "twenty-five billion, five hundred five million, two hundred eighty-seven thousand, seven hundred ninety-one".