198778 has 8 divisors (see below), whose sum is σ = 313920. Its totient is φ = 94140.

The previous prime is 198769. The next prime is 198811. The reversal of 198778 is 877891.

It is a sphenic number, since it is the product of 3 distinct primes.

It is an Ulam number.

It is a self number, because there is not a number n which added to its sum of digits gives 198778.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2578 + ... + 2653.

It is an arithmetic number, because the mean of its divisors is an integer number (39240).

2¹⁹⁸⁷⁷⁸ is an apocalyptic number.

198778 is a deficient number, since it is larger than the sum of its proper divisors (115142).

198778 is a wasteful number, since it uses less digits than its factorization.

198778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5252.

The product of its digits is 28224, while the sum is 40.

The square root of 198778 is about 445.8452646379. The cubic root of 198778 is about 58.3610063711.

The spelling of 198778 in words is "one hundred ninety-eight thousand, seven hundred seventy-eight".