321620336657 has 2 divisors, whose sum is σ = 321620336658. Its totient is φ = 321620336656.

The previous prime is 321620336633. The next prime is 321620336671. The reversal of 321620336657 is 756633026123.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 256409564161 + 65210772496 = 506369^2 + 255364^2 .

It is a cyclic number.

It is not a de Polignac number, because 321620336657 - 2¹⁰ = 321620335633 is a prime.

It is not a weakly prime, because it can be changed into another prime (321620336857) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 160810168328 + 160810168329.

It is an arithmetic number, because the mean of its divisors is an integer number (160810168329).

Almost surely, 2^321620336657 is an apocalyptic number.

It is an amenable number.

321620336657 is a deficient number, since it is larger than the sum of its proper divisors (1).

321620336657 is an equidigital number, since it uses as much as digits as its factorization.

321620336657 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 816480, while the sum is 44.

The spelling of 321620336657 in words is "three hundred twenty-one billion, six hundred twenty million, three hundred thirty-six thousand, six hundred fifty-seven".