668786209 has 16 divisors (see below), whose sum is σ = 825045760. Its totient is φ = 527912640.

The previous prime is 668786207. The next prime is 668786231. The reversal of 668786209 is 902687866.

It is a cyclic number.

It is not a de Polignac number, because 668786209 - 2¹ = 668786207 is a prime.

It is not an unprimeable number, because it can be changed into a prime (668786201) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 31579 + ... + 48319.

It is an arithmetic number, because the mean of its divisors is an integer number (51565360).

Almost surely, 2^668786209 is an apocalyptic number.

It is an amenable number.

668786209 is a deficient number, since it is larger than the sum of its proper divisors (156259551).

668786209 is a wasteful number, since it uses less digits than its factorization.

668786209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17200.

The product of its (nonzero) digits is 1741824, while the sum is 52.

The square root of 668786209 is about 25860.9011637259. The cubic root of 668786209 is about 874.5052807226.

The spelling of 668786209 in words is "six hundred sixty-eight million, seven hundred eighty-six thousand, two hundred nine".