198234721 has 4 divisors (see below), whose sum is σ = 198263700. Its totient is φ = 198205744.

The previous prime is 198234679. The next prime is 198234731. The reversal of 198234721 is 127432891.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 48441600 + 149793121 = 6960^2 + 12239^2 .

It is a cyclic number.

It is not a de Polignac number, because 198234721 - 2⁷ = 198234593 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (198234731) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2115 + ... + 20023.

It is an arithmetic number, because the mean of its divisors is an integer number (49565925).

Almost surely, 2^198234721 is an apocalyptic number.

It is an amenable number.

198234721 is a deficient number, since it is larger than the sum of its proper divisors (28979).

198234721 is a wasteful number, since it uses less digits than its factorization.

198234721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28978.

The product of its digits is 24192, while the sum is 37.

The square root of 198234721 is about 14079.5852566757. The cubic root of 198234721 is about 583.0778914961.

The spelling of 198234721 in words is "one hundred ninety-eight million, two hundred thirty-four thousand, seven hundred twenty-one".