199985018 has 4 divisors (see below), whose sum is σ = 299977530. Its totient is φ = 99992508.

The previous prime is 199985011. The next prime is 199985021. The reversal of 199985018 is 810589991.

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., 150381169 + 49603849 = 12263^2 + 7043^2 .

It is not an unprimeable number, because it can be changed into a prime (199985011) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49996253 + ... + 49996256.

Almost surely, 2^199985018 is an apocalyptic number.

199985018 is a deficient number, since it is larger than the sum of its proper divisors (99992512).

199985018 is an equidigital number, since it uses as much as digits as its factorization.

199985018 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 99992511.

The product of its (nonzero) digits is 233280, while the sum is 50.

The square root of 199985018 is about 14141.6059201210. The cubic root of 199985018 is about 584.7889447333.

The spelling of 199985018 in words is "one hundred ninety-nine million, nine hundred eighty-five thousand, eighteen".