191998 has 8 divisors (see below), whose sum is σ = 304992. Its totient is φ = 90336.

The previous prime is 191977. The next prime is 191999. The reversal of 191998 is 899191.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (191999) 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, 2790 + ... + 2857.

It is an arithmetic number, because the mean of its divisors is an integer number (38124).

2¹⁹¹⁹⁹⁸ is an apocalyptic number.

191998 is a deficient number, since it is larger than the sum of its proper divisors (112994).

191998 is a wasteful number, since it uses less digits than its factorization.

191998 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5666.

The product of its digits is 5832, while the sum is 37.

The square root of 191998 is about 438.1757638209. The cubic root of 191998 is about 57.6897824992.

The spelling of 191998 in words is "one hundred ninety-one thousand, nine hundred ninety-eight".