660688 has 40 divisors (see below), whose sum is σ = 1553472. Its totient is φ = 265728.

The previous prime is 660683. The next prime is 660719. The reversal of 660688 is 886066.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (34).

It is a congruent number.

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

660688 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1731 + ... + 2077.

2⁶⁶⁰⁶⁸⁸ is an apocalyptic number.

660688 is a gapful number since it is divisible by the number (68) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 660688, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (776736).

660688 is an abundant number, since it is smaller than the sum of its proper divisors (892784).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

660688 is a wasteful number, since it uses less digits than its factorization.

660688 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 379 (or 373 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 34.

The square root of 660688 is about 812.8271649004. The cubic root of 660688 is about 87.0961195992.

The spelling of 660688 in words is "six hundred sixty thousand, six hundred eighty-eight".