321566512550561 has 2 divisors, whose sum is σ = 321566512550562. Its totient is φ = 321566512550560.

The previous prime is 321566512550539. The next prime is 321566512550597. The reversal of 321566512550561 is 165055215665123.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 180500057970961 + 141066454579600 = 13435031^2 + 11877140^2 .

It is a cyclic number.

It is not a de Polignac number, because 321566512550561 - 2⁶ = 321566512550497 is a prime.

It is not a weakly prime, because it can be changed into another prime (321566512550861) 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, 160783256275280 + 160783256275281.

It is an arithmetic number, because the mean of its divisors is an integer number (160783256275281).

Almost surely, 2^{321566512550561} is an apocalyptic number.

It is an amenable number.

321566512550561 is a deficient number, since it is larger than the sum of its proper divisors (1).

321566512550561 is an equidigital number, since it uses as much as digits as its factorization.

321566512550561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8100000, while the sum is 53.

The spelling of 321566512550561 in words is "three hundred twenty-one trillion, five hundred sixty-six billion, five hundred twelve million, five hundred fifty thousand, five hundred sixty-one".