678545865 has 12 divisors (see below), whose sum is σ = 1176146244. Its totient is φ = 361891104.

The previous prime is 678545821. The next prime is 678545867. The reversal of 678545865 is 568545876.

678545865 is a `hidden beast` number, since 6 + 7 + 8 + 54 + 586 + 5 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 213539769 + 465006096 = 14613^2 + 21564^2 .

It is not a de Polignac number, because 678545865 - 2⁹ = 678545353 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (678545867) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 7539354 + ... + 7539443.

It is an arithmetic number, because the mean of its divisors is an integer number (98012187).

Almost surely, 2^678545865 is an apocalyptic number.

It is an amenable number.

678545865 is a deficient number, since it is larger than the sum of its proper divisors (497600379).

678545865 is a wasteful number, since it uses less digits than its factorization.

678545865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15078808 (or 15078805 counting only the distinct ones).

The product of its digits is 8064000, while the sum is 54.

The square root of 678545865 is about 26048.9129331725. The cubic root of 678545865 is about 878.7386651418.

It can be divided in two parts, 6785 and 45865, that added together give a triangular number (52650 = T₃₂₄).

The spelling of 678545865 in words is "six hundred seventy-eight million, five hundred forty-five thousand, eight hundred sixty-five".