199996987 has 2 divisors, whose sum is σ = 199996988. Its totient is φ = 199996986.

The previous prime is 199996981. The next prime is 199996991. The reversal of 199996987 is 789699991.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 199996987 - 2¹⁹ = 199472699 is a prime.

It is not a weakly prime, because it can be changed into another prime (199996981) 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, 99998493 + 99998494.

It is an arithmetic number, because the mean of its divisors is an integer number (99998494).

Almost surely, 2^199996987 is an apocalyptic number.

199996987 is a deficient number, since it is larger than the sum of its proper divisors (1).

199996987 is an equidigital number, since it uses as much as digits as its factorization.

199996987 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 19840464, while the sum is 67.

The square root of 199996987 is about 14142.0290976932. The cubic root of 199996987 is about 584.8006109393.

The spelling of 199996987 in words is "one hundred ninety-nine million, nine hundred ninety-six thousand, nine hundred eighty-seven".