678706705 has 4 divisors (see below), whose sum is σ = 814448052. Its totient is φ = 542965360.

The previous prime is 678706627. The next prime is 678706729. The reversal of 678706705 is 507607876.

It is a Cunningham number, because it is equal to 26052²+1.

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

It can be written as a sum of positive squares in 2 ways, for example, as 244359424 + 434347281 = 15632^2 + 20841^2 .

It is not a de Polignac number, because 678706705 - 2²³ = 670318097 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 67870666 + ... + 67870675.

It is an arithmetic number, because the mean of its divisors is an integer number (203612013).

Almost surely, 2^678706705 is an apocalyptic number.

It is an amenable number.

678706705 is a deficient number, since it is larger than the sum of its proper divisors (135741347).

678706705 is a wasteful number, since it uses less digits than its factorization.

678706705 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 135741346.

The product of its (nonzero) digits is 493920, while the sum is 46.

The square root of 678706705 is about 26052.0000191924. Note that the first 4 decimals coincide. The cubic root of 678706705 is about 878.8080906434.

The spelling of 678706705 in words is "six hundred seventy-eight million, seven hundred six thousand, seven hundred five".