678912779 has 4 divisors (see below), whose sum is σ = 678975960. Its totient is φ = 678849600.

The previous prime is 678912763. The next prime is 678912821. The reversal of 678912779 is 977219876.

678912779 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 678912779 - 2⁴ = 678912763 is a prime.

It is a super-2 number, since 2×678912779² = 921845122979005682, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (678912709) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10997 + ... + 38454.

It is an arithmetic number, because the mean of its divisors is an integer number (169743990).

Almost surely, 2^678912779 is an apocalyptic number.

678912779 is a deficient number, since it is larger than the sum of its proper divisors (63181).

678912779 is a wasteful number, since it uses less digits than its factorization.

678912779 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 63180.

The product of its digits is 2667168, while the sum is 56.

The square root of 678912779 is about 26055.9547704551. The cubic root of 678912779 is about 878.8970250689.

The spelling of 678912779 in words is "six hundred seventy-eight million, nine hundred twelve thousand, seven hundred seventy-nine".