198259891 has 4 divisors (see below), whose sum is σ = 198527472. Its totient is φ = 197992312.

The previous prime is 198259861. The next prime is 198259913. The reversal of 198259891 is 198952891.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 198952891 = 251 ⋅792641.

It is a cyclic number.

It is not a de Polignac number, because 198259891 - 2²¹ = 196162739 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (198259861) 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, 132676 + ... + 134161.

It is an arithmetic number, because the mean of its divisors is an integer number (49631868).

Almost surely, 2^198259891 is an apocalyptic number.

198259891 is a deficient number, since it is larger than the sum of its proper divisors (267581).

198259891 is an equidigital number, since it uses as much as digits as its factorization.

198259891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 267580.

The product of its digits is 466560, while the sum is 52.

The square root of 198259891 is about 14080.4790756565. The cubic root of 198259891 is about 583.1025683865.

The spelling of 198259891 in words is "one hundred ninety-eight million, two hundred fifty-nine thousand, eight hundred ninety-one".