19873778489 has 2 divisors, whose sum is σ = 19873778490. Its totient is φ = 19873778488.

The previous prime is 19873778471. The next prime is 19873778531. The reversal of 19873778489 is 98487737891.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12931556089 + 6942222400 = 113717^2 + 83320^2 .

It is a cyclic number.

It is not a de Polignac number, because 19873778489 - 2²⁰ = 19872729913 is a prime.

It is not a weakly prime, because it can be changed into another prime (19873778459) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9936889244 + 9936889245.

It is an arithmetic number, because the mean of its divisors is an integer number (9936889245).

Almost surely, 2^19873778489 is an apocalyptic number.

It is an amenable number.

19873778489 is a deficient number, since it is larger than the sum of its proper divisors (1).

19873778489 is an equidigital number, since it uses as much as digits as its factorization.

19873778489 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 170698752, while the sum is 71.

The spelling of 19873778489 in words is "nineteen billion, eight hundred seventy-three million, seven hundred seventy-eight thousand, four hundred eighty-nine".