321356426561 has 2 divisors, whose sum is σ = 321356426562. Its totient is φ = 321356426560.

The previous prime is 321356426549. The next prime is 321356426579. The reversal of 321356426561 is 165624653123.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 168744316225 + 152612110336 = 410785^2 + 390656^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-321356426561 is a prime.

It is not a weakly prime, because it can be changed into another prime (321356426761) 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 as a sum of consecutive naturals, namely, 160678213280 + 160678213281.

It is an arithmetic number, because the mean of its divisors is an integer number (160678213281).

Almost surely, 2^321356426561 is an apocalyptic number.

It is an amenable number.

321356426561 is a deficient number, since it is larger than the sum of its proper divisors (1).

321356426561 is an equidigital number, since it uses as much as digits as its factorization.

321356426561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 777600, while the sum is 44.

The spelling of 321356426561 in words is "three hundred twenty-one billion, three hundred fifty-six million, four hundred twenty-six thousand, five hundred sixty-one".