198288509 has 4 divisors (see below), whose sum is σ = 198428316. Its totient is φ = 198148704.

The previous prime is 198288481. The next prime is 198288521. The reversal of 198288509 is 905882891.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 104489284 + 93799225 = 10222^2 + 9685^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-198288509 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (198288539) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 67754 + ... + 70619.

It is an arithmetic number, because the mean of its divisors is an integer number (49607079).

Almost surely, 2^198288509 is an apocalyptic number.

It is an amenable number.

198288509 is a deficient number, since it is larger than the sum of its proper divisors (139807).

198288509 is a wasteful number, since it uses less digits than its factorization.

198288509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 139806.

The product of its (nonzero) digits is 414720, while the sum is 50.

The square root of 198288509 is about 14081.4952686141. The cubic root of 198288509 is about 583.1306231893.

The spelling of 198288509 in words is "one hundred ninety-eight million, two hundred eighty-eight thousand, five hundred nine".