198431221 has 4 divisors (see below), whose sum is σ = 198507232. Its totient is φ = 198355212.

The previous prime is 198431209. The next prime is 198431263. The reversal of 198431221 is 122134891.

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, and also an emirpimes, since its reverse is a distinct semiprime: 122134891 = 37 ⋅3300943.

It is a cyclic number.

It is not a de Polignac number, because 198431221 - 2⁹ = 198430709 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 (198431291) 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, 33945 + ... + 39358.

It is an arithmetic number, because the mean of its divisors is an integer number (49626808).

Almost surely, 2^198431221 is an apocalyptic number.

It is an amenable number.

198431221 is a deficient number, since it is larger than the sum of its proper divisors (76011).

198431221 is an equidigital number, since it uses as much as digits as its factorization.

198431221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 76010.

The product of its digits is 3456, while the sum is 31.

The square root of 198431221 is about 14086.5617167569. The cubic root of 198431221 is about 583.2704863630.

The spelling of 198431221 in words is "one hundred ninety-eight million, four hundred thirty-one thousand, two hundred twenty-one".