25640445601165 has 4 divisors (see below), whose sum is σ = 30768534721404. Its totient is φ = 20512356480928.

The previous prime is 25640445601123. The next prime is 25640445601181. The reversal of 25640445601165 is 56110654404652.

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 8171439596329 + 17469006004836 = 2858573^2 + 4179594^2 .

It is a cyclic number.

It is not a de Polignac number, because 25640445601165 - 2²⁷ = 25640311383437 is a prime.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2564044560112 + ... + 2564044560121.

It is an arithmetic number, because the mean of its divisors is an integer number (7692133680351).

Almost surely, 2^{25640445601165} is an apocalyptic number.

It is an amenable number.

25640445601165 is a deficient number, since it is larger than the sum of its proper divisors (5128089120239).

25640445601165 is an equidigital number, since it uses as much as digits as its factorization.

25640445601165 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5128089120238.

The product of its (nonzero) digits is 3456000, while the sum is 49.

The spelling of 25640445601165 in words is "twenty-five trillion, six hundred forty billion, four hundred forty-five million, six hundred one thousand, one hundred sixty-five".