660681 has 12 divisors (see below), whose sum is σ = 1090752. Its totient is φ = 377496.

The previous prime is 660661. The next prime is 660683. The reversal of 660681 is 186066.

It is not a de Polignac number, because 660681 - 2⁶ = 660617 is a prime.

It is a super-2 number, since 2×660681² = 872998767522, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (660683) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 5181 + ... + 5306.

It is an arithmetic number, because the mean of its divisors is an integer number (90896).

2⁶⁶⁰⁶⁸¹ is an apocalyptic number.

It is an amenable number.

660681 is a deficient number, since it is larger than the sum of its proper divisors (430071).

660681 is a wasteful number, since it uses less digits than its factorization.

660681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10500 (or 10497 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The square root of 660681 is about 812.8228589305. The cubic root of 660681 is about 87.0958120032.

The spelling of 660681 in words is "six hundred sixty thousand, six hundred eighty-one".