19993321 has 2 divisors, whose sum is σ = 19993322. Its totient is φ = 19993320.

The previous prime is 19993319. The next prime is 19993327. The reversal of 19993321 is 12339991.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18826921 + 1166400 = 4339^2 + 1080^2 .

It is a cyclic number.

It is not a de Polignac number, because 19993321 - 2¹ = 19993319 is a prime.

Together with 19993319, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (19993327) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9996660 + 9996661.

It is an arithmetic number, because the mean of its divisors is an integer number (9996661).

Almost surely, 2^19993321 is an apocalyptic number.

It is an amenable number.

19993321 is a deficient number, since it is larger than the sum of its proper divisors (1).

19993321 is an equidigital number, since it uses as much as digits as its factorization.

19993321 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 13122, while the sum is 37.

The square root of 19993321 is about 4471.3891577451. The cubic root of 19993321 is about 271.4115423032.

The spelling of 19993321 in words is "nineteen million, nine hundred ninety-three thousand, three hundred twenty-one".