198959987 has 2 divisors, whose sum is σ = 198959988. Its totient is φ = 198959986.

The previous prime is 198959983. The next prime is 198960007. The reversal of 198959987 is 789959891.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 198959987 - 2² = 198959983 is a prime.

It is not a weakly prime, because it can be changed into another prime (198959983) 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, 99479993 + 99479994.

It is an arithmetic number, because the mean of its divisors is an integer number (99479994).

Almost surely, 2^198959987 is an apocalyptic number.

198959987 is a deficient number, since it is larger than the sum of its proper divisors (1).

198959987 is an equidigital number, since it uses as much as digits as its factorization.

198959987 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 14696640, while the sum is 65.

The square root of 198959987 is about 14105.3176851853. The cubic root of 198959987 is about 583.7881133419.

The spelling of 198959987 in words is "one hundred ninety-eight million, nine hundred fifty-nine thousand, nine hundred eighty-seven".