199711979 has 2 divisors, whose sum is σ = 199711980. Its totient is φ = 199711978.

The previous prime is 199711973. The next prime is 199711997. The reversal of 199711979 is 979117991.

Together with next prime (199711997) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It is an emirp because it is prime and its reverse (979117991) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 199711979 - 2¹⁶ = 199646443 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 199711979.

It is not a weakly prime, because it can be changed into another prime (199711973) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99855989 + 99855990.

It is an arithmetic number, because the mean of its divisors is an integer number (99855990).

Almost surely, 2^199711979 is an apocalyptic number.

199711979 is a deficient number, since it is larger than the sum of its proper divisors (1).

199711979 is an equidigital number, since it uses as much as digits as its factorization.

199711979 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 321489, while the sum is 53.

The square root of 199711979 is about 14131.9488748014. The cubic root of 199711979 is about 584.5226866053.

The spelling of 199711979 in words is "one hundred ninety-nine million, seven hundred eleven thousand, nine hundred seventy-nine".