198640009 has 8 divisors (see below), whose sum is σ = 200196800. Its totient is φ = 197089200.

The previous prime is 198640007. The next prime is 198640021. The reversal of 198640009 is 900046891.

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

It is a cyclic number.

It is not a de Polignac number, because 198640009 - 2¹ = 198640007 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 198640009.

It is not an unprimeable number, because it can be changed into a prime (198640007) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 82594 + ... + 84964.

It is an arithmetic number, because the mean of its divisors is an integer number (25024600).

Almost surely, 2^198640009 is an apocalyptic number.

It is an amenable number.

198640009 is a deficient number, since it is larger than the sum of its proper divisors (1556791).

198640009 is a wasteful number, since it uses less digits than its factorization.

198640009 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2991.

The product of its (nonzero) digits is 15552, while the sum is 37.

The square root of 198640009 is about 14093.9706612438. The cubic root of 198640009 is about 583.4749857536.

The spelling of 198640009 in words is "one hundred ninety-eight million, six hundred forty thousand, nine".