19993889 has 2 divisors, whose sum is σ = 19993890. Its totient is φ = 19993888.

The previous prime is 19993849. The next prime is 19993891. The reversal of 19993889 is 98839991.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17497489 + 2496400 = 4183^2 + 1580^2 .

It is a cyclic number.

It is not a de Polignac number, because 19993889 - 2¹⁶ = 19928353 is a prime.

Together with 19993891, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (19993849) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9996944 + 9996945.

It is an arithmetic number, because the mean of its divisors is an integer number (9996945).

Almost surely, 2^19993889 is an apocalyptic number.

It is an amenable number.

19993889 is a deficient number, since it is larger than the sum of its proper divisors (1).

19993889 is an equidigital number, since it uses as much as digits as its factorization.

19993889 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1259712, while the sum is 56.

The square root of 19993889 is about 4471.4526722308. The cubic root of 19993889 is about 271.4141124998.

The spelling of 19993889 in words is "nineteen million, nine hundred ninety-three thousand, eight hundred eighty-nine".