19765388661 has 4 divisors (see below), whose sum is σ = 26353851552. Its totient is φ = 13176925772.

The previous prime is 19765388627. The next prime is 19765388693. The reversal of 19765388661 is 16688356791.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 19765388661 - 2¹³ = 19765380469 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 19765388595 and 19765388604.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19765348661) 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 in 3 ways as a sum of consecutive naturals, for example, 3294231441 + ... + 3294231446.

It is an arithmetic number, because the mean of its divisors is an integer number (6588462888).

Almost surely, 2^19765388661 is an apocalyptic number.

It is an amenable number.

19765388661 is a deficient number, since it is larger than the sum of its proper divisors (6588462891).

19765388661 is an equidigital number, since it uses as much as digits as its factorization.

19765388661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6588462890.

The product of its digits is 13063680, while the sum is 60.

The spelling of 19765388661 in words is "nineteen billion, seven hundred sixty-five million, three hundred eighty-eight thousand, six hundred sixty-one".