199890779 has 4 divisors (see below), whose sum is σ = 218062680. Its totient is φ = 181718880.

The previous prime is 199890767. The next prime is 199890781. The reversal of 199890779 is 977098991.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 199890779 - 2⁴ = 199890763 is a prime.

It is not an unprimeable number, because it can be changed into a prime (199890739) 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 3 ways as a sum of consecutive naturals, for example, 9085934 + ... + 9085955.

It is an arithmetic number, because the mean of its divisors is an integer number (54515670).

Almost surely, 2^199890779 is an apocalyptic number.

199890779 is a deficient number, since it is larger than the sum of its proper divisors (18171901).

199890779 is a wasteful number, since it uses less digits than its factorization.

199890779 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18171900.

The product of its (nonzero) digits is 2571912, while the sum is 59.

The square root of 199890779 is about 14138.2735508972. The cubic root of 199890779 is about 584.6970735444.

The spelling of 199890779 in words is "one hundred ninety-nine million, eight hundred ninety thousand, seven hundred seventy-nine".