198999985 has 8 divisors (see below), whose sum is σ = 239651496. Its totient is φ = 158632320.

The previous prime is 198999967. The next prime is 199000003. The reversal of 198999985 is 589999891.

It is an interprime number because it is at equal distance from previous prime (198999967) and next prime (199000003).

It can be written as a sum of positive squares in 4 ways, for example, as 64625521 + 134374464 = 8039^2 + 11592^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a de Polignac number, because none of the positive numbers 2^k-198999985 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 198999985.

It is an unprimeable number.

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 in 7 ways as a sum of consecutive naturals, for example, 69414 + ... + 72223.

It is an arithmetic number, because the mean of its divisors is an integer number (29956437).

Almost surely, 2^198999985 is an apocalyptic number.

It is an amenable number.

198999985 is a deficient number, since it is larger than the sum of its proper divisors (40651511).

198999985 is a wasteful number, since it uses less digits than its factorization.

198999985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 141923.

The product of its digits is 18895680, while the sum is 67.

The square root of 198999985 is about 14106.7354480050. The cubic root of 198999985 is about 583.8272314124.

The spelling of 198999985 in words is "one hundred ninety-eight million, nine hundred ninety-nine thousand, nine hundred eighty-five".