198021 has 8 divisors (see below), whose sum is σ = 266400. Its totient is φ = 130832.

The previous prime is 198017. The next prime is 198031. The reversal of 198021 is 120891.

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

It is a cyclic number.

It is not a de Polignac number, because 198021 - 2² = 198017 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (198031) 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 7 ways as a sum of consecutive naturals, for example, 226 + ... + 668.

It is an arithmetic number, because the mean of its divisors is an integer number (33300).

2¹⁹⁸⁰²¹ is an apocalyptic number.

It is an amenable number.

198021 is a deficient number, since it is larger than the sum of its proper divisors (68379).

198021 is a wasteful number, since it uses less digits than its factorization.

198021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 595.

The product of its (nonzero) digits is 144, while the sum is 21.

The square root of 198021 is about 444.9955055953. The cubic root of 198021 is about 58.2868273322.

The spelling of 198021 in words is "one hundred ninety-eight thousand, twenty-one".