668739601 has 4 divisors (see below), whose sum is σ = 668846772. Its totient is φ = 668632432.

The previous prime is 668739527. The next prime is 668739613. The reversal of 668739601 is 106937866.

It is a Cunningham number, because it is equal to 25860²+1.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 16192576 + 652547025 = 4024^2 + 25545^2 .

It is a cyclic number.

It is not a de Polignac number, because 668739601 - 2⁷ = 668739473 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (668739671) 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, 43606 + ... + 56911.

It is an arithmetic number, because the mean of its divisors is an integer number (167211693).

Almost surely, 2^668739601 is an apocalyptic number.

It is an amenable number.

668739601 is a deficient number, since it is larger than the sum of its proper divisors (107171).

668739601 is a wasteful number, since it uses less digits than its factorization.

668739601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 107170.

The product of its (nonzero) digits is 326592, while the sum is 46.

The square root of 668739601 is about 25860.0000193349. Note that the first 4 decimals coincide. The cubic root of 668739601 is about 874.4849653670.

The spelling of 668739601 in words is "six hundred sixty-eight million, seven hundred thirty-nine thousand, six hundred one".