19785567493 has 2 divisors, whose sum is σ = 19785567494. Its totient is φ = 19785567492.

The previous prime is 19785567469. The next prime is 19785567533. The reversal of 19785567493 is 39476558791.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17382312964 + 2403254529 = 131842^2 + 49023^2 .

It is an emirp because it is prime and its reverse (39476558791) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-19785567493 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19785564493) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9892783746 + 9892783747.

It is an arithmetic number, because the mean of its divisors is an integer number (9892783747).

Almost surely, 2^19785567493 is an apocalyptic number.

It is an amenable number.

19785567493 is a deficient number, since it is larger than the sum of its proper divisors (1).

19785567493 is an equidigital number, since it uses as much as digits as its factorization.

19785567493 is an evil number, because the sum of its binary digits is even.

The product of its digits is 57153600, while the sum is 64.

The spelling of 19785567493 in words is "nineteen billion, seven hundred eighty-five million, five hundred sixty-seven thousand, four hundred ninety-three".