668781065 has 8 divisors (see below), whose sum is σ = 805983048. Its totient is φ = 532727680.

The previous prime is 668781041. The next prime is 668781079. The reversal of 668781065 is 560187866.

668781065 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 22401289 + 646379776 = 4733^2 + 25424^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 668781065 - 2²⁰ = 667732489 is a prime.

It is a super-3 number, since 3×668781065³ (a number of 27 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 285866 + ... + 288195.

It is an arithmetic number, because the mean of its divisors is an integer number (100747881).

Almost surely, 2^668781065 is an apocalyptic number.

It is an amenable number.

668781065 is a deficient number, since it is larger than the sum of its proper divisors (137201983).

668781065 is a wasteful number, since it uses less digits than its factorization.

668781065 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 574299.

The product of its (nonzero) digits is 483840, while the sum is 47.

The square root of 668781065 is about 25860.8017083771. The cubic root of 668781065 is about 874.5030386176.

The spelling of 668781065 in words is "six hundred sixty-eight million, seven hundred eighty-one thousand, sixty-five".