999999778 has 16 divisors (see below), whose sum is σ = 1519718400. Its totient is φ = 493468416.

The previous prime is 999999761. The next prime is 999999797. The reversal of 999999778 is 877999999.

999999778 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 38823 + ... + 59221.

It is an arithmetic number, because the mean of its divisors is an integer number (94982400).

Almost surely, 2^999999778 is an apocalyptic number.

999999778 is a deficient number, since it is larger than the sum of its proper divisors (519718622).

999999778 is a wasteful number, since it uses less digits than its factorization.

999999778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20721.

The product of its digits is 208324872, while the sum is 76.

The square root of 999999778 is about 31622.7730915554. The cubic root of 999999778 is about 999.9999260000. Note that the first 4 decimals are identical.

The spelling of 999999778 in words is "nine hundred ninety-nine million, nine hundred ninety-nine thousand, seven hundred seventy-eight".