19966144687 has 2 divisors, whose sum is σ = 19966144688. Its totient is φ = 19966144686.

The previous prime is 19966144657. The next prime is 19966144697. The reversal of 19966144687 is 78644166991.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 19966144687 - 2¹¹ = 19966142639 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19966144637) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9983072343 + 9983072344.

It is an arithmetic number, because the mean of its divisors is an integer number (9983072344).

Almost surely, 2^19966144687 is an apocalyptic number.

19966144687 is a deficient number, since it is larger than the sum of its proper divisors (1).

19966144687 is an equidigital number, since it uses as much as digits as its factorization.

19966144687 is an evil number, because the sum of its binary digits is even.

The product of its digits is 15676416, while the sum is 61.

The spelling of 19966144687 in words is "nineteen billion, nine hundred sixty-six million, one hundred forty-four thousand, six hundred eighty-seven".