19861659428497 has 2 divisors, whose sum is σ = 19861659428498. Its totient is φ = 19861659428496.

The previous prime is 19861659428411. The next prime is 19861659428581. The reversal of 19861659428497 is 79482495616891.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14239634319936 + 5622025108561 = 3773544^2 + 2371081^2 .

It is an emirp because it is prime and its reverse (79482495616891) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 19861659428497 - 2¹⁹ = 19861658904209 is a prime.

It is not a weakly prime, because it can be changed into another prime (19861659428407) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9930829714248 + 9930829714249.

It is an arithmetic number, because the mean of its divisors is an integer number (9930829714249).

Almost surely, 2^{19861659428497} is an apocalyptic number.

It is an amenable number.

19861659428497 is a deficient number, since it is larger than the sum of its proper divisors (1).

19861659428497 is an equidigital number, since it uses as much as digits as its factorization.

19861659428497 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1881169920, while the sum is 79.

The spelling of 19861659428497 in words is "nineteen trillion, eight hundred sixty-one billion, six hundred fifty-nine million, four hundred twenty-eight thousand, four hundred ninety-seven".