2644636661321 has 4 divisors (see below), whose sum is σ = 2655987033492. Its totient is φ = 2633286289152.

The previous prime is 2644636661311. The next prime is 2644636661369. The reversal of 2644636661321 is 1231666364462.

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 1681119696400 + 963516964921 = 1296580^2 + 981589^2 .

It is a cyclic number.

It is not a de Polignac number, because 2644636661321 - 2¹⁸ = 2644636399177 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 2644636661321.

It is not an unprimeable number, because it can be changed into a prime (2644636661311) 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, 5675185736 + ... + 5675186201.

It is an arithmetic number, because the mean of its divisors is an integer number (663996758373).

Almost surely, 2^{2644636661321} is an apocalyptic number.

It is an amenable number.

2644636661321 is a deficient number, since it is larger than the sum of its proper divisors (11350372171).

2644636661321 is a wasteful number, since it uses less digits than its factorization.

2644636661321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11350372170.

The product of its digits is 4478976, while the sum is 50.

The spelling of 2644636661321 in words is "two trillion, six hundred forty-four billion, six hundred thirty-six million, six hundred sixty-one thousand, three hundred twenty-one".