2780661328265 has 4 divisors (see below), whose sum is σ = 3336793593924. Its totient is φ = 2224529062608.

The previous prime is 2780661328261. The next prime is 2780661328267. The reversal of 2780661328265 is 5628231660872.

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 1982903320336 + 797758007929 = 1408156^2 + 893173^2 .

It is a cyclic number.

It is not a de Polignac number, because 2780661328265 - 2² = 2780661328261 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 2780661328265.

It is not an unprimeable number, because it can be changed into a prime (2780661328261) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 278066132822 + ... + 278066132831.

It is an arithmetic number, because the mean of its divisors is an integer number (834198398481).

Almost surely, 2^{2780661328265} is an apocalyptic number.

It is an amenable number.

2780661328265 is a deficient number, since it is larger than the sum of its proper divisors (556132265659).

2780661328265 is an equidigital number, since it uses as much as digits as its factorization.

2780661328265 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 556132265658.

The product of its (nonzero) digits is 11612160, while the sum is 56.

The spelling of 2780661328265 in words is "two trillion, seven hundred eighty billion, six hundred sixty-one million, three hundred twenty-eight thousand, two hundred sixty-five".