678612779 has 4 divisors (see below), whose sum is σ = 730813776. Its totient is φ = 626411784.

The previous prime is 678612773. The next prime is 678612787. The reversal of 678612779 is 977216876.

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 678612779 - 2²⁰ = 677564203 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 678612779.

It is not an unprimeable number, because it can be changed into a prime (678612773) 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, 26100479 + ... + 26100504.

It is an arithmetic number, because the mean of its divisors is an integer number (182703444).

Almost surely, 2^678612779 is an apocalyptic number.

678612779 is a deficient number, since it is larger than the sum of its proper divisors (52200997).

678612779 is a wasteful number, since it uses less digits than its factorization.

678612779 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52200996.

The product of its digits is 1778112, while the sum is 53.

The square root of 678612779 is about 26050.1972929189. The cubic root of 678612779 is about 878.7675494513.

The spelling of 678612779 in words is "six hundred seventy-eight million, six hundred twelve thousand, seven hundred seventy-nine".