198752190809 has 4 divisors (see below), whose sum is σ = 205605714660. Its totient is φ = 191898666960.

The previous prime is 198752190781. The next prime is 198752190883. The reversal of 198752190809 is 908091257891.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 908091257891 = 2731 ⋅332512361.

It can be written as a sum of positive squares in 2 ways, for example, as 171263545600 + 27488645209 = 413840^2 + 165797^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-198752190809 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (198752195809) 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, 3426761882 + ... + 3426761939.

It is an arithmetic number, because the mean of its divisors is an integer number (51401428665).

Almost surely, 2^198752190809 is an apocalyptic number.

It is an amenable number.

198752190809 is a deficient number, since it is larger than the sum of its proper divisors (6853523851).

198752190809 is an equidigital number, since it uses as much as digits as its factorization.

198752190809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6853523850.

The product of its (nonzero) digits is 3265920, while the sum is 59.

The spelling of 198752190809 in words is "one hundred ninety-eight billion, seven hundred fifty-two million, one hundred ninety thousand, eight hundred nine".