199999931 has 2 divisors, whose sum is σ = 199999932.
Its totient is φ = 199999930.
The previous prime is 199999903. The next prime is 199999949. The reversal of 199999931 is 139999991.
It is a strong prime.
It is an emirp because it is prime and its reverse (139999991) is a distict prime.
It is a cyclic number.
It is not a de Polignac number, because 199999931 - 210 = 199998907 is a prime.
It is a super-2 number, since 2×1999999312 = 79999944800009522, which contains 22 as substring.
It is not a weakly prime, because it can be changed into another prime (199999901) by changing a digit.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99999965 + 99999966.
It is an arithmetic number, because the mean of its divisors is an integer number (99999966).
Almost surely, 2199999931 is an apocalyptic number.
199999931 is a deficient number, since it is larger than the sum of its proper divisors (1).
199999931 is an equidigital number, since it uses as much as digits as its factorization.
199999931 is an evil number, because the sum of its binary digits is even.
The product of its digits is 1594323, while the sum is 59.
The square root of 199999931 is about 14142.1331842123.
The cubic root of 199999931 is about 584.8034803902.
The spelling of 199999931 in words is "one hundred ninety-nine million, nine hundred ninety-nine thousand, nine hundred thirty-one".