25649508865 has 4 divisors (see below), whose sum is σ = 30779410644. Its totient is φ = 20519607088.

The previous prime is 25649508821. The next prime is 25649508877. The reversal of 25649508865 is 56880594652.

It is a happy number.

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 19952127504 + 5697381361 = 141252^2 + 75481^2 .

It is a cyclic number.

It is not a de Polignac number, because 25649508865 - 2¹³ = 25649500673 is a prime.

It is a Duffinian 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, 2564950882 + ... + 2564950891.

It is an arithmetic number, because the mean of its divisors is an integer number (7694852661).

Almost surely, 2^25649508865 is an apocalyptic number.

It is an amenable number.

25649508865 is a deficient number, since it is larger than the sum of its proper divisors (5129901779).

25649508865 is an equidigital number, since it uses as much as digits as its factorization.

25649508865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5129901778.

The product of its (nonzero) digits is 20736000, while the sum is 58.

The spelling of 25649508865 in words is "twenty-five billion, six hundred forty-nine million, five hundred eight thousand, eight hundred sixty-five".