198251818 has 4 divisors (see below), whose sum is σ = 297377730. Its totient is φ = 99125908.

The previous prime is 198251791. The next prime is 198251819. The reversal of 198251818 is 818152891.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 180552969 + 17698849 = 13437^2 + 4207^2 .

It is not an unprimeable number, because it can be changed into a prime (198251819) 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 as a sum of consecutive naturals, namely, 49562953 + ... + 49562956.

Almost surely, 2^198251818 is an apocalyptic number.

198251818 is a deficient number, since it is larger than the sum of its proper divisors (99125912).

198251818 is an equidigital number, since it uses as much as digits as its factorization.

198251818 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 99125911.

The product of its digits is 46080, while the sum is 43.

The square root of 198251818 is about 14080.1923992536. The cubic root of 198251818 is about 583.0946537735.

The spelling of 198251818 in words is "one hundred ninety-eight million, two hundred fifty-one thousand, eight hundred eighteen".