198421 has 4 divisors (see below), whose sum is σ = 207072. Its totient is φ = 189772.

The previous prime is 198413. The next prime is 198427. The reversal of 198421 is 124891.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 198421 - 2³ = 198413 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (198427) 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, 4291 + ... + 4336.

It is an arithmetic number, because the mean of its divisors is an integer number (51768).

2¹⁹⁸⁴²¹ is an apocalyptic number.

It is an amenable number.

198421 is a deficient number, since it is larger than the sum of its proper divisors (8651).

198421 is an equidigital number, since it uses as much as digits as its factorization.

198421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8650.

The product of its digits is 576, while the sum is 25.

The square root of 198421 is about 445.4447215985. Note that the first 3 decimals coincide. The cubic root of 198421 is about 58.3260471625.

The spelling of 198421 in words is "one hundred ninety-eight thousand, four hundred twenty-one".