668729 has 8 divisors (see below), whose sum is σ = 715680. Its totient is φ = 622656.

The previous prime is 668719. The next prime is 668737. The reversal of 668729 is 927866.

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 668729 - 2⁴ = 668713 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 668692 and 668701.

It is not an unprimeable number, because it can be changed into a prime (668719) 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, 2222 + ... + 2504.

It is an arithmetic number, because the mean of its divisors is an integer number (89460).

2⁶⁶⁸⁷²⁹ is an apocalyptic number.

It is an amenable number.

668729 is a deficient number, since it is larger than the sum of its proper divisors (46951).

668729 is a wasteful number, since it uses less digits than its factorization.

668729 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 439.

The product of its digits is 36288, while the sum is 38.

The square root of 668729 is about 817.7585218144. The cubic root of 668729 is about 87.4480344503.

The spelling of 668729 in words is "six hundred sixty-eight thousand, seven hundred twenty-nine".