9778998779 has 4 divisors (see below), whose sum is σ = 10667998680. Its totient is φ = 8889998880.

The previous prime is 9778998773. The next prime is 9778998797.

9778998779 is nontrivially palindromic in base 10.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-9778998779 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (9778998773) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 444499934 + ... + 444499955.

It is an arithmetic number, because the mean of its divisors is an integer number (2666999670).

Almost surely, 2^9778998779 is an apocalyptic number.

9778998779 is a deficient number, since it is larger than the sum of its proper divisors (888999901).

9778998779 is a wasteful number, since it uses less digits than its factorization.

9778998779 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 888999900.

The product of its digits is 1008189504, while the sum is 80.

The square root of 9778998779 is about 98888.8202932971. The cubic root of 9778998779 is about 2138.4452254592.

The spelling of 9778998779 in words is "nine billion, seven hundred seventy-eight million, nine hundred ninety-eight thousand, seven hundred seventy-nine".