198525809 has 4 divisors (see below), whose sum is σ = 198784740. Its totient is φ = 198266880.

The previous prime is 198525739. The next prime is 198525823. The reversal of 198525809 is 908525891.

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 142874209 + 55651600 = 11953^2 + 7460^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-198525809 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (198525409) 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, 128312 + ... + 129849.

It is an arithmetic number, because the mean of its divisors is an integer number (49696185).

Almost surely, 2^198525809 is an apocalyptic number.

It is an amenable number.

198525809 is a deficient number, since it is larger than the sum of its proper divisors (258931).

198525809 is an equidigital number, since it uses as much as digits as its factorization.

198525809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 258930.

The product of its (nonzero) digits is 259200, while the sum is 47.

The square root of 198525809 is about 14089.9187009720. The cubic root of 198525809 is about 583.3631492424.

The spelling of 198525809 in words is "one hundred ninety-eight million, five hundred twenty-five thousand, eight hundred nine".