678665249 has 4 divisors (see below), whose sum is σ = 685254336. Its totient is φ = 672076164.

The previous prime is 678665227. The next prime is 678665261. The reversal of 678665249 is 942566876.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 678665249 - 2⁸ = 678664993 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 678665249.

It is not an unprimeable number, because it can be changed into a prime (678665149) by changing a digit.

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, 3294389 + ... + 3294594.

It is an arithmetic number, because the mean of its divisors is an integer number (171313584).

Almost surely, 2^678665249 is an apocalyptic number.

It is an amenable number.

678665249 is a deficient number, since it is larger than the sum of its proper divisors (6589087).

678665249 is a wasteful number, since it uses less digits than its factorization.

678665249 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6589086.

The product of its digits is 4354560, while the sum is 53.

The square root of 678665249 is about 26051.2043675528. The cubic root of 678665249 is about 878.7901974898.

The spelling of 678665249 in words is "six hundred seventy-eight million, six hundred sixty-five thousand, two hundred forty-nine".