19619861689 has 2 divisors, whose sum is σ = 19619861690. Its totient is φ = 19619861688.

The previous prime is 19619861663. The next prime is 19619861707. The reversal of 19619861689 is 98616891691.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16452423289 + 3167438400 = 128267^2 + 56280^2 .

It is an emirp because it is prime and its reverse (98616891691) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 19619861689 - 2¹⁹ = 19619337401 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 19619861689.

It is not a weakly prime, because it can be changed into another prime (19619861629) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9809930844 + 9809930845.

It is an arithmetic number, because the mean of its divisors is an integer number (9809930845).

Almost surely, 2^19619861689 is an apocalyptic number.

It is an amenable number.

19619861689 is a deficient number, since it is larger than the sum of its proper divisors (1).

19619861689 is an equidigital number, since it uses as much as digits as its factorization.

19619861689 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10077696, while the sum is 64.

The spelling of 19619861689 in words is "nineteen billion, six hundred nineteen million, eight hundred sixty-one thousand, six hundred eighty-nine".