668844817 has 8 divisors (see below), whose sum is σ = 675881024. Its totient is φ = 661819248.

The previous prime is 668844763. The next prime is 668844829. The reversal of 668844817 is 718448866.

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

It is a cyclic number.

It is not a de Polignac number, because 668844817 - 2⁷ = 668844689 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (668844877) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 209878 + ... + 213040.

It is an arithmetic number, because the mean of its divisors is an integer number (84485128).

Almost surely, 2^668844817 is an apocalyptic number.

It is an amenable number.

668844817 is a deficient number, since it is larger than the sum of its proper divisors (7036207).

668844817 is a wasteful number, since it uses less digits than its factorization.

668844817 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5319.

The product of its digits is 2064384, while the sum is 52.

The square root of 668844817 is about 25862.0342780687. The cubic root of 668844817 is about 874.5308252627.

The spelling of 668844817 in words is "six hundred sixty-eight million, eight hundred forty-four thousand, eight hundred seventeen".