19718712861 has 4 divisors (see below), whose sum is σ = 26291617152. Its totient is φ = 13145808572.

The previous prime is 19718712847. The next prime is 19718712869. The reversal of 19718712861 is 16821781791.

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 19718712861 - 2²² = 19714518557 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19718712869) 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, 3286452141 + ... + 3286452146.

It is an arithmetic number, because the mean of its divisors is an integer number (6572904288).

Almost surely, 2^19718712861 is an apocalyptic number.

It is an amenable number.

19718712861 is a deficient number, since it is larger than the sum of its proper divisors (6572904291).

19718712861 is an equidigital number, since it uses as much as digits as its factorization.

19718712861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6572904290.

The product of its digits is 338688, while the sum is 51.

The spelling of 19718712861 in words is "nineteen billion, seven hundred eighteen million, seven hundred twelve thousand, eight hundred sixty-one".