668731 has 8 divisors (see below), whose sum is σ = 774144. Its totient is φ = 565800.

The previous prime is 668719. The next prime is 668737. The reversal of 668731 is 137866.

668731 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 668731 - 2⁵ = 668699 is a prime.

It is a super-2 number, since 2×668731² = 894402300722, which contains 22 as substring.

It is a nialpdrome in base 15.

It is a junction number, because it is equal to n+sod(n) for n = 668693 and 668702.

It is not an unprimeable number, because it can be changed into a prime (668737) 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, 6 + ... + 1156.

It is an arithmetic number, because the mean of its divisors is an integer number (96768).

2⁶⁶⁸⁷³¹ is an apocalyptic number.

668731 is a deficient number, since it is larger than the sum of its proper divisors (105413).

668731 is a wasteful number, since it uses less digits than its factorization.

668731 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1241.

The product of its digits is 6048, while the sum is 31.

The square root of 668731 is about 817.7597446683. The cubic root of 668731 is about 87.4481216286.

The spelling of 668731 in words is "six hundred sixty-eight thousand, seven hundred thirty-one".