199998981 has 24 divisors (see below), whose sum is σ = 355555200. Its totient is φ = 105493536.

The previous prime is 199998971. The next prime is 199998989. The reversal of 199998981 is 189899991.

It is not a de Polignac number, because 199998981 - 2⁶ = 199998917 is a prime.

It is a super-2 number, since 2×199998981² = 79999184802076722, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (199998989) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 121281 + ... + 122918.

It is an arithmetic number, because the mean of its divisors is an integer number (14814800).

Almost surely, 2^199998981 is an apocalyptic number.

It is an amenable number.

199998981 is a deficient number, since it is larger than the sum of its proper divisors (155556219).

199998981 is a wasteful number, since it uses less digits than its factorization.

199998981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 244225 (or 244222 counting only the distinct ones).

The product of its digits is 3779136, while the sum is 63.

The square root of 199998981 is about 14142.0995965946. The cubic root of 199998981 is about 584.8025544495.

The spelling of 199998981 in words is "one hundred ninety-nine million, nine hundred ninety-eight thousand, nine hundred eighty-one".