19968545489 has 2 divisors, whose sum is σ = 19968545490. Its totient is φ = 19968545488.

The previous prime is 19968545483. The next prime is 19968545507. The reversal of 19968545489 is 98454586991.

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., 12948619264 + 7019926225 = 113792^2 + 83785^2 .

It is a cyclic number.

It is not a de Polignac number, because 19968545489 - 2¹⁶ = 19968479953 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 (19968545483) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9984272744 + 9984272745.

It is an arithmetic number, because the mean of its divisors is an integer number (9984272745).

Almost surely, 2^19968545489 is an apocalyptic number.

It is an amenable number.

19968545489 is a deficient number, since it is larger than the sum of its proper divisors (1).

19968545489 is an equidigital number, since it uses as much as digits as its factorization.

19968545489 is an evil number, because the sum of its binary digits is even.

The product of its digits is 111974400, while the sum is 68.

The spelling of 19968545489 in words is "nineteen billion, nine hundred sixty-eight million, five hundred forty-five thousand, four hundred eighty-nine".