199968779 has 2 divisors, whose sum is σ = 199968780. Its totient is φ = 199968778.

The previous prime is 199968763. The next prime is 199968781. The reversal of 199968779 is 977869991.

199968779 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 199968779 - 2⁴ = 199968763 is a prime.

Together with 199968781, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (199968719) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99984389 + 99984390.

It is an arithmetic number, because the mean of its divisors is an integer number (99984390).

Almost surely, 2^199968779 is an apocalyptic number.

199968779 is a deficient number, since it is larger than the sum of its proper divisors (1).

199968779 is an equidigital number, since it uses as much as digits as its factorization.

199968779 is an evil number, because the sum of its binary digits is even.

The product of its digits is 15431472, while the sum is 65.

The square root of 199968779 is about 14141.0317516085. The cubic root of 199968779 is about 584.7731158064.

The spelling of 199968779 in words is "one hundred ninety-nine million, nine hundred sixty-eight thousand, seven hundred seventy-nine".