198739 has 4 divisors (see below), whose sum is σ = 199656. Its totient is φ = 197824.

The previous prime is 198733. The next prime is 198761. The reversal of 198739 is 937891.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-198739 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 198698 and 198707.

It is not an unprimeable number, because it can be changed into a prime (198733) 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, 72 + ... + 634.

It is an arithmetic number, because the mean of its divisors is an integer number (49914).

2¹⁹⁸⁷³⁹ is an apocalyptic number.

198739 is a deficient number, since it is larger than the sum of its proper divisors (917).

198739 is an equidigital number, since it uses as much as digits as its factorization.

198739 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 916.

The product of its digits is 13608, while the sum is 37.

The square root of 198739 is about 445.8015253451. The cubic root of 198739 is about 58.3571893355.

The spelling of 198739 in words is "one hundred ninety-eight thousand, seven hundred thirty-nine".