19807975861 has 2 divisors, whose sum is σ = 19807975862. Its totient is φ = 19807975860.

The previous prime is 19807975823. The next prime is 19807975909. The reversal of 19807975861 is 16857970891.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10587175236 + 9220800625 = 102894^2 + 96025^2 .

It is an emirp because it is prime and its reverse (16857970891) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 19807975861 - 2⁹ = 19807975349 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 19807975861.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19807975261) 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, 9903987930 + 9903987931.

It is an arithmetic number, because the mean of its divisors is an integer number (9903987931).

Almost surely, 2^19807975861 is an apocalyptic number.

It is an amenable number.

19807975861 is a deficient number, since it is larger than the sum of its proper divisors (1).

19807975861 is an equidigital number, since it uses as much as digits as its factorization.

19807975861 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7620480, while the sum is 61.

The spelling of 19807975861 in words is "nineteen billion, eight hundred seven million, nine hundred seventy-five thousand, eight hundred sixty-one".