199811931 has 16 divisors (see below), whose sum is σ = 307732608. Its totient is φ = 113974400.

The previous prime is 199811917. The next prime is 199811977. The reversal of 199811931 is 139118991.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 199811931 - 2¹³ = 199803739 is a prime.

It is a super-2 number, since 2×199811931² = 79849615539897522, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (199811981) 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 15 ways as a sum of consecutive naturals, for example, 177525 + ... + 178646.

It is an arithmetic number, because the mean of its divisors is an integer number (19233288).

Almost surely, 2^199811931 is an apocalyptic number.

199811931 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

199811931 is a deficient number, since it is larger than the sum of its proper divisors (107920677).

199811931 is a wasteful number, since it uses less digits than its factorization.

199811931 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 356202.

The product of its digits is 17496, while the sum is 42.

The square root of 199811931 is about 14135.4848165884. The cubic root of 199811931 is about 584.6201844583.

It can be divided in two parts, 19981 and 1931, that added together give a palindrome (21912).

The spelling of 199811931 in words is "one hundred ninety-nine million, eight hundred eleven thousand, nine hundred thirty-one".