198567921 has 4 divisors (see below), whose sum is σ = 264757232. Its totient is φ = 132378612.

The previous prime is 198567911. The next prime is 198567949. The reversal of 198567921 is 129765891.

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 not a de Polignac number, because 198567921 - 2⁷ = 198567793 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (198567911) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 33094651 + ... + 33094656.

It is an arithmetic number, because the mean of its divisors is an integer number (66189308).

Almost surely, 2^198567921 is an apocalyptic number.

It is an amenable number.

198567921 is a deficient number, since it is larger than the sum of its proper divisors (66189311).

198567921 is an equidigital number, since it uses as much as digits as its factorization.

198567921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66189310.

The product of its digits is 272160, while the sum is 48.

The square root of 198567921 is about 14091.4130235403. The cubic root of 198567921 is about 583.4043946809.

The spelling of 198567921 in words is "one hundred ninety-eight million, five hundred sixty-seven thousand, nine hundred twenty-one".