25640128249 has 4 divisors (see below), whose sum is σ = 25640454400. Its totient is φ = 25639802100.

The previous prime is 25640128247. The next prime is 25640128271. The reversal of 25640128249 is 94282104652.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 25640128249 - 2¹ = 25640128247 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (25640128247) 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, 35224 + ... + 229174.

It is an arithmetic number, because the mean of its divisors is an integer number (6410113600).

Almost surely, 2^25640128249 is an apocalyptic number.

It is an amenable number.

25640128249 is a deficient number, since it is larger than the sum of its proper divisors (326151).

25640128249 is a wasteful number, since it uses less digits than its factorization.

25640128249 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 326150.

The product of its (nonzero) digits is 276480, while the sum is 43.

The spelling of 25640128249 in words is "twenty-five billion, six hundred forty million, one hundred twenty-eight thousand, two hundred forty-nine".