6811663814321 has 2 divisors, whose sum is σ = 6811663814322. Its totient is φ = 6811663814320.

The previous prime is 6811663814309. The next prime is 6811663814353. The reversal of 6811663814321 is 1234183661186.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 6403106350096 + 408557464225 = 2530436^2 + 639185^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6811663814321 is a prime.

It is a super-2 number, since 2×6811663814321² (a number of 26 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 6811663814321.

It is not a weakly prime, because it can be changed into another prime (6811663814621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3405831907160 + 3405831907161.

It is an arithmetic number, because the mean of its divisors is an integer number (3405831907161).

Almost surely, 2^{6811663814321} is an apocalyptic number.

It is an amenable number.

6811663814321 is a deficient number, since it is larger than the sum of its proper divisors (1).

6811663814321 is an equidigital number, since it uses as much as digits as its factorization.

6811663814321 is an evil number, because the sum of its binary digits is even.

The product of its digits is 995328, while the sum is 50.

The spelling of 6811663814321 in words is "six trillion, eight hundred eleven billion, six hundred sixty-three million, eight hundred fourteen thousand, three hundred twenty-one".