668318647 has 4 divisors (see below), whose sum is σ = 670110760. Its totient is φ = 666526536.

The previous prime is 668318621. The next prime is 668318681. The reversal of 668318647 is 746813866.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 746813866 = 2 ⋅373406933.

It is a cyclic number.

It is not a de Polignac number, because 668318647 - 2¹¹ = 668316599 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 668318647.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (668318447) 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, 895497 + ... + 896242.

It is an arithmetic number, because the mean of its divisors is an integer number (167527690).

Almost surely, 2^668318647 is an apocalyptic number.

668318647 is a deficient number, since it is larger than the sum of its proper divisors (1792113).

668318647 is a wasteful number, since it uses less digits than its factorization.

668318647 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1792112.

The product of its digits is 1161216, while the sum is 49.

The square root of 668318647 is about 25851.8596429735. The cubic root of 668318647 is about 874.3014384203.

The spelling of 668318647 in words is "six hundred sixty-eight million, three hundred eighteen thousand, six hundred forty-seven".