198857 has 4 divisors (see below), whose sum is σ = 203136. Its totient is φ = 194580.

The previous prime is 198851. The next prime is 198859. The reversal of 198857 is 758891.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 758891 = 7 ⋅108413.

It is not a de Polignac number, because 198857 - 2⁴ = 198841 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 198857.

It is not an unprimeable number, because it can be changed into a prime (198851) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2069 + ... + 2162.

It is an arithmetic number, because the mean of its divisors is an integer number (50784).

2¹⁹⁸⁸⁵⁷ is an apocalyptic number.

It is an amenable number.

198857 is a deficient number, since it is larger than the sum of its proper divisors (4279).

198857 is an equidigital number, since it uses as much as digits as its factorization.

198857 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4278.

The product of its digits is 20160, while the sum is 38.

The square root of 198857 is about 445.9338515968. The cubic root of 198857 is about 58.3687367854.

The spelling of 198857 in words is "one hundred ninety-eight thousand, eight hundred fifty-seven".