199680881 has 2 divisors, whose sum is σ = 199680882.
Its totient is φ = 199680880.
The previous prime is 199680857. The next prime is 199680883. The reversal of 199680881 is 188086991.
It is a happy number.
It is a strong prime.
It can be written as a sum of positive squares in only one way, i.e., 153983281 + 45697600 = 12409^2 + 6760^2
It is an emirp because it is prime and its reverse (188086991) is a distict prime.
It is also a bemirp because it and its reverse can be mirrored producing other two distinct primes, 188089661 and 166980881.
It is a cyclic number.
It is not a de Polignac number, because 199680881 - 214 = 199664497 is a prime.
It is a super-2 number, since 2×1996808812 = 79744908473872322, which contains 22 as substring.
It is a Sophie Germain prime.
Together with 199680883, it forms a pair of twin primes.
It is a Chen prime.
It is a Curzon number.
It is not a weakly prime, because it can be changed into another prime (199680883) 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 as a sum of consecutive naturals, namely, 99840440 + 99840441.
It is an arithmetic number, because the mean of its divisors is an integer number (99840441).
Almost surely, 2199680881 is an apocalyptic number.
It is an amenable number.
199680881 is a deficient number, since it is larger than the sum of its proper divisors (1).
199680881 is an equidigital number, since it uses as much as digits as its factorization.
199680881 is an odious number, because the sum of its binary digits is odd.
The product of its (nonzero) digits is 248832, while the sum is 50.
The square root of 199680881 is about 14130.8485590923.
The cubic root of 199680881 is about 584.4923455275.
The spelling of 199680881 in words is "one hundred ninety-nine million, six hundred eighty thousand, eight hundred eighty-one".