19990221593 has 2 divisors, whose sum is σ = 19990221594. Its totient is φ = 19990221592.

The previous prime is 19990221571. The next prime is 19990221631. The reversal of 19990221593 is 39512209991.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15943607824 + 4046613769 = 126268^2 + 63613^2 .

It is a cyclic number.

It is not a de Polignac number, because 19990221593 - 2⁶ = 19990221529 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (19990221533) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9995110796 + 9995110797.

It is an arithmetic number, because the mean of its divisors is an integer number (9995110797).

Almost surely, 2^19990221593 is an apocalyptic number.

It is an amenable number.

19990221593 is a deficient number, since it is larger than the sum of its proper divisors (1).

19990221593 is an equidigital number, since it uses as much as digits as its factorization.

19990221593 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 393660, while the sum is 50.

The spelling of 19990221593 in words is "nineteen billion, nine hundred ninety million, two hundred twenty-one thousand, five hundred ninety-three".