198878891 has 2 divisors, whose sum is σ = 198878892. Its totient is φ = 198878890.

The previous prime is 198878879. The next prime is 198878917.

It is a happy number.

198878891 is nontrivially palindromic in base 10.

It is a weak prime.

It is a palprime.

It is a cyclic number.

It is not a de Polignac number, because 198878891 - 2¹⁴ = 198862507 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 198878891.

It is not a weakly prime, because it can be changed into another prime (198878851) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99439445 + 99439446.

It is an arithmetic number, because the mean of its divisors is an integer number (99439446).

Almost surely, 2^198878891 is an apocalyptic number.

198878891 is a deficient number, since it is larger than the sum of its proper divisors (1).

198878891 is an equidigital number, since it uses as much as digits as its factorization.

198878891 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2322432, while the sum is 59.

The square root of 198878891 is about 14102.4427316689. The cubic root of 198878891 is about 583.7087853066.

The spelling of 198878891 in words is "one hundred ninety-eight million, eight hundred seventy-eight thousand, eight hundred ninety-one".