19988321 has 2 divisors, whose sum is σ = 19988322. Its totient is φ = 19988320.

The previous prime is 19988291. The next prime is 19988333. The reversal of 19988321 is 12388991.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19891600 + 96721 = 4460^2 + 311^2 .

It is an emirp because it is prime and its reverse (12388991) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 19988321 - 2⁶ = 19988257 is a prime.

It is not a weakly prime, because it can be changed into another prime (19948321) by changing a digit.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9994160 + 9994161.

It is an arithmetic number, because the mean of its divisors is an integer number (9994161).

Almost surely, 2^19988321 is an apocalyptic number.

It is an amenable number.

19988321 is a deficient number, since it is larger than the sum of its proper divisors (1).

19988321 is an equidigital number, since it uses as much as digits as its factorization.

19988321 is an evil number, because the sum of its binary digits is even.

The product of its digits is 31104, while the sum is 41.

The square root of 19988321 is about 4470.8300124250. The cubic root of 19988321 is about 271.3889152327.

The spelling of 19988321 in words is "nineteen million, nine hundred eighty-eight thousand, three hundred twenty-one".