19557368393221 has 2 divisors, whose sum is σ = 19557368393222. Its totient is φ = 19557368393220.

The previous prime is 19557368393177. The next prime is 19557368393279. The reversal of 19557368393221 is 12239386375591.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17018718890625 + 2538649502596 = 4125375^2 + 1593314^2 .

It is an emirp because it is prime and its reverse (12239386375591) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 19557368393221 - 2⁷ = 19557368393093 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19557368397221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9778684196610 + 9778684196611.

It is an arithmetic number, because the mean of its divisors is an integer number (9778684196611).

Almost surely, 2^{19557368393221} is an apocalyptic number.

It is an amenable number.

19557368393221 is a deficient number, since it is larger than the sum of its proper divisors (1).

19557368393221 is an equidigital number, since it uses as much as digits as its factorization.

19557368393221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 73483200, while the sum is 64.

The spelling of 19557368393221 in words is "nineteen trillion, five hundred fifty-seven billion, three hundred sixty-eight million, three hundred ninety-three thousand, two hundred twenty-one".