19555784987 has 2 divisors, whose sum is σ = 19555784988. Its totient is φ = 19555784986.

The previous prime is 19555784953. The next prime is 19555784999. The reversal of 19555784987 is 78948755591.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 19555784987 - 2¹⁰ = 19555783963 is a prime.

It is not a weakly prime, because it can be changed into another prime (19555784917) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9777892493 + 9777892494.

It is an arithmetic number, because the mean of its divisors is an integer number (9777892494).

Almost surely, 2^19555784987 is an apocalyptic number.

19555784987 is a deficient number, since it is larger than the sum of its proper divisors (1).

19555784987 is an equidigital number, since it uses as much as digits as its factorization.

19555784987 is an evil number, because the sum of its binary digits is even.

The product of its digits is 127008000, while the sum is 68.

The spelling of 19555784987 in words is "nineteen billion, five hundred fifty-five million, seven hundred eighty-four thousand, nine hundred eighty-seven".